HARI SREENIVASAN: We turn to the crisis in Turkey, where the government continued its crackdown on those involved in an attempted coup that left more than 250 dead and nearly 2,000 injured. Leaders from around the world are calling for restraint.

"NewsHour" special correspondent Marcia Biggs is in Istanbul and has the latest.

MARCIA BIGGS, Special Correspondent: Protests raged for yet another day in Istanbul's Taksim Square. Supporters of President Recep Tayyip Erdogan vowing to protect their leader and Turkey's fragile democracy.

That fury was channeled by Turkey's prime minister, who said the country will evaluate whether to reinstate the death penalty for some who plotted the coup. Turkey had scrapped capital punishment as part of its ongoing bid to join the European Union.

BINALI YILDIRIM, Prime Minister, Turkey (through translator): Death penalty requires a change of constitution. We will decide in compliance with the people's will.

MARCIA BIGGS: That brought a swift rebuke from the E.U. foreign policy chief, Federica Mogherini, and others in Europe.

FEDERICA MOGHERINI, Foreign Policy Chief, European Union: We are the ones saying today rule of law has to be protected in the country. There is no excuse for any steps that takes the country away from that.

MARCIA BIGGS: Mogherini spoke before meetings in Brussels with Secretary of State John Kerry and other foreign ministers. Kerry pledged support for Turkey's government, but cautioned the U.S. and others will be watching closely.

JOHN KERRY, Secretary of State: NATO also has a requirement with respect to democracy, and NATO will indeed measure very carefully what is happening.

MARCIA BIGGS: A major point of contention between the U.S. and Turkey, the fate of Muslim cleric and Erdogan opponent Fethullah Gulen, who lives in Pennsylvania in self-imposed exile. Erdogan and his administration say Gulen orchestrated the coup attempt, a charge the cleric forcefully denies.

Turkey is demanding he be extradited. The coup attempt by factions of Turkey's military launched a night of terror late Friday. President Erdogan, who was on vacation, spoke first via FaceTime on Turkish TV and called for his supporters to take to the streets.

Then, late at night, he flew into Istanbul's airport and vowed to purge the military and government.

PRESIDENT RECEP TAYYIP ERDOGAN, Turkey (through translator): Those guns were given to you by the people of this country. If you use the guns against the people who gave them to you, you will pay a heavy price.

MARCIA BIGGS: Chaos continued through the night, but by midday Saturday, the strike against the state was largely defeated. Erdogan has moved swiftly to make good on his vow to purge the country of what he calls conspirators; 9,000 police and other security officials were fired today.

More than 6,000 military personnel have been detained, and more than 3,000 judges suspended. Offices of many Turkish media organizations were stormed Friday night, including state television and CNN's Turkish network.

Murat Yetkin is editor-in-chief of Hurriyet Daily News, whose office was also taken hostage.

QUESTION: Is he in control?

MURAT YETKIN, Editor-in-Chief, Hurriyet Daily News: It's president's quote, prime minister's quote that everything is not over yet. That means they're not.

QUESTION: Well, and if it were over, he wouldn't be still calling people out into the street.

MURAT YETKIN: No.

MARCIA BIGGS: So, the question remains, who has emerged the true winner?

MURAT YETKIN: Erdogan's popularity has increased.

MARCIA BIGGS: Whether in favor of President Erdogan or not, most people we spoke to agreed that military rule wasn't the answer. Where the people remain bitterly divided is over the future identity of their government, Islamic or secular.

Tarkan runs this cafe in a secular neighborhood. He says his biggest fear is that his two small children will not live in a free Turkey.

His friend Enre is a 31-year-old gay photographer. When demonstrators took to the streets on Friday, he says he felt targeted and with no one to call for protection.

ENRE: I don't feel any safe really in my country now.

WOMAN: Basically, we are not (INAUDIBLE) people, because we are wearing short skirt, dress, and drinking the alcohol and going to bars.

MARCIA BIGGS: Thirty-five-year-old Burcu is terrified of the Erdogan government's promise to institute aspects of Islamic law into the traditionally secular Turkish legal system.

WOMAN (through translator): They're telling us protect your democracy, but this is not what I understand democracy to be or what I want from my democracy. For the last two days in this country, there have been calls for jihad and people have been going out to the streets with machetes.

MARCIA BIGGS: In this neighborhood, the people we met were scared, sad, and desperately uncertain of their future. Not a 10-minute walk away, we met 48-year-old Taci and his family. Taci took his son with him out on the streets Friday night in support of President Erdogan. He praises the president for what he has done for the economy and scoffs at suggestions that Turkey under his rule has lost its freedom.

MAN (through translator): Look around. Everyone can dress as they want. There'll be no Sharia law brought to Turkey. This will never happen.

MARCIA BIGGS: His wife, Hulya, tells us that Erdogan is the strong leader the country needs and she is pleased that her children can now attend religion classes at school, as part of a program initiated by Erdogan for what he calls the devout generation.

WOMAN (through translator): If we had Sharia law now, the heads of these generals who attempted the coup would be hanging at the palace gates. There was no mercy during Ottoman time under Sharia law. We want capital punishment. We want it deep from our hearts. And it will happen, inshallah.

MARCIA BIGGS: Strong opinions on both sides and looming uncertainty for a divided country in a fragile state.

For the "PBS NewsHour," I'm Marcia Biggs in Istanbul, Turkey.

HARI SREENIVASAN: For more on this, we turn to Soner Cagaptay, director of the Turkish Research Program at the Washington Institute for Near East Policy. He's also the author of "The Rise of Turkey: The 21st Century's First Muslim Power." And "NewsHour" chief foreign affairs correspondent Margaret Warner.

Soner, first, I want to ask, the information coming out of Turkey says the Interior Ministry has fired close to 9,000 people. Were that many people involved in this coup?

SONER CAGAPTAY, The Washington Institute for Near East Policy: Probably not.

It's likely that the military plotters of the coup that the government arrested were involved in it, but I can't believe that 9,000 judges and many other civilian employees were involved in the coup. Rather, what this suggests is that the government is now going after the Gulen movement, which was its former ally, also a conservative movement as the AKP's is.

But now since the rift, 2013, there has been a blood feud between the two, and it's not a coincidence therefore that there were some Gulen-aligned officers who probably took part in this coup effort. But the government is casting a wider net and going after what it thinks are supporters and sympathizers of this movement in the bureaucracy and also in the judiciary.

So expect a large-scale witch-hunt in Turkey coming up.

HARI SREENIVASAN: We will talk a little bit more about Gulen in a second, but, Margaret, what is the U.S. kind of position on what looks like a large-scale crackdown?

MARGARET WARNER, Chief Foreign Affairs Correspondent: Well, that is exactly the number one U.S. concern.

The U.S. was caught off-guard by this, Hari, and certainly came out and said the right things about supporting a democratic government, but quickly followed by admonitions to Erdogan not to use this as a way to purge, as he has in others — in journalist community and the judiciary, purge people he thinks are his opponents.

And when Secretary Kerry made his first comments, I think it was on Saturday, and suggested at least in the reporting that Turkey's NATO membership might be affected by this, there was a huge reaction from Turkish diplomats, who peppered the State Department and the White House demanding an explanation.

And so today you saw the White House press secretary taking concerns — taking care to say, look, Turkey is a member, and it's a member. This is not like the E.U.. But there's certainly concern in the White House that this is going to deepen the rift with Turkey, the chilly relationship.

The labor minister even suggested the U.S. was behind the coup. Erdogan hasn't repeated that, but there are deep concerns.

HARI SREENIVASAN: Let's talk a little bit about Fethullah Gulen.

He's in Pennsylvania. Erdogan says he's behind the coup. He says, I'm not behind the coup. Secretary Kerry says prove that he's behind the coup.

Who is he and does he have the kind of influence that scares Erdogan so much?

SONER CAGAPTAY: He's known to have friends in the Turkish bureaucracy, including in the police force, as well as the judiciary and the military.

And after the rift started with him and President Erdogan, many Gulen-aligned or suspected Gulen-aligned people in the bureaucracy were kicked out. Now this gives Erdogan a second chance to really go after this movement.

I think at the end, whether or not we think Gulen movement was behind the coup fully, this is what President Erdogan believes. He believes that this is the main driving force behind the coup and he will go after them with all his force. And whereas earlier, the whole issue of Gulen movement was a talking point in U.S.-Turkish relationship when there were bilateral meetings, now it's going to be issue number one.

Erdogan is going to insist on his extradition and he might even link Turkish-U.S. cooperation on Gulen's extradition. Now, that may not work with the Pentagon, which already has a dim view of Erdogan's administration for his policy of allowing radicals to cross into Syria to fight the Assad regime, some of whom have morphed into ISIS.

So, if he does link those two, I think that might create a backlash at the Pentagon. People might say, we don't want a deal like that. I think what Turkey ought to do is separate the two issues, provide to Washington a full and convincing account of, as they say, Gulen's involvement in the coup, but keep military cooperation separate from that.

HARI SREENIVASAN: Margaret, what Soner is pointing to is just also the geographic and political importance of Turkey right now and how important it is to the United States and really all NATO allies, especially in the fight against ISIS.

MARGARET WARNER: Incirlik Air Base, it's mostly a Turkish base. And the U.S. just has a little section there.

But some of the coup plotters, including the former commander of the base who tried to get asylum from the U.S., ostensibly or reportedly or accusedly were working out of there. It's all very uncomfortable. The power has not even been restored to the air base, but the U.S. has its own power.

But if you look at a map, Turkey is absolutely key now, given its related involvement in the fight against ISIS, in which it really is cracking down on people trying to get in and most importantly letting U.S. planes use that, not only to refuel, but to launch offensive strikes.

Otherwise, they have to come from carriers in the ocean, taking five, six times as much and often having to leave without even dropping their ordnance. Maintaining this relationship, you can see the United States trying very hard to manage it, so it doesn't go awry, as Soner was suggesting.

SONER CAGAPTAY: There will be problems moving forward, because of the fact that there is really no good outcome of this coup for Turkey.

If the military had won, it would have become an oppressive country. And Erdogan has won, but it still will become a oppressive place, because he has a record of cracking down on dissent, and going after the opposition, banning social media, sending the police to beat up demonstrators.

And so far Erdogan has done all of this based on the assumption that there is a conspiracy to overthrow him. Now that theory has legs, because there really is a conspiracy to overthrow him. His supporters will embrace his crackdown as oppression as a necessary tool to go after those who want to undermine him, and he will continue casting a wide net against the opposition.

While Turkey has the right, an Erdogan administration, to go after those who executed this ill-conceived, ill-executed, nefarious plot, I think we're going to see that his crackdown is going to be wider than that going after the opposition. It will become much more difficult for Turks who don't agree with him to oppose his policies democratically.

MARGARET WARNER: The U.S. view is, we will know in two weeks whether it's that or whether they're just rounding up a lot of suspects and that in two weeks most are freed and they really identify coup plotters.

HARI SREENIVASAN: All right, Soner Cagaptay and Margaret Warner, thanks so much.

SONER CAGAPTAY: It's a pleasure.

MARGARET WARNER: Pleasure.