Updated at 11:55 p.m. ET
Turkish President Recep Tayyip Erdogan has addressed the public for a second time since some members of the military launched a coup attempt against him.
Speaking outside the airport at Istanbul, Erdogan said, "They have pointed the people's guns against the people. The president, whom 52 percent of the people brought to power, is in charge."
Erdogan was on holiday when the revolt started, but returned and has been at the airport since then.
Earlier he gave a news conference in which he said the plot is a reason to "clean up" the armed forces.
Local media quote the prosecutor's office in Ankara, Turkey, as saying at least 42 people have been killed during the attempted coup.
One of the key locations taken by the rebel troops was the Bosporus bridge, and early on Saturday private broadcaster CNN Turk showed video of dozens of soldiers surrendering there.
Turkish Prime Minister Binali Yildirim says more than 130 people have been arrested.
The state-run Anadolu news agency says Istanbul's Ataturk airport, which had been shut down, has returned to normal operations.
Our previous post continues:
As military vehicles rumbled through the streets of Ankara, members of Turkey's military said Friday night they had seized control of the country, ousting President Recep Tayyip Erdogan, who has dominated the country for more than a decade.
The dramatic development plunged one of the region's most important countries into a major crisis. Television footage showed civilians coming into the streets in many places, with some waving red-and-white Turkish flags. However, it was not clear who was supporting the coup and who was opposing it.
Erdogan had been on vacation at the Black Sea, but his exact whereabouts were not immediately clear. The Turkish president — who has censored social media — did appear via FaceTime video on the CNN Turk network and called on the Turkish people to resist the military action.
"I urge the Turkish people to convene at public squares and airports," he said. "I never believed in a power higher than the power of the people."
Hundreds of people flooded the streets of multiple Turkish cities including Istanbul. Images on local media showed some people trying to block the way of tanks and others standing face to face with soldiers blocking a bridge.
Erdogan said he was on his way to Ankara, the capital, though he did not say where he was when he spoke to the network. Erdogan, who has ruled as either prime minister or president since 2003, won several elections, most recently in 2014. But he had a prickly relationship with the powerful military, which has carried out multiple coups since 1960.
U.S. Secretary of State John Kerry said he spoke with Turkey's foreign minister "and emphasized the United States' absolute support for Turkey's democratically elected, civilian government and democratic institutions."
However, shortly after coup rumors began, a Turkish state television broadcaster read a statement saying members of the military had taken over the country and that the military was giving the orders. It was not clear exactly who within the military was behind the coup attempt, or how widespread support was in the military.
Shortly after that, state broadcaster TRT went off the air, but it has since been restored.
Also, the state news agency said the chief of staff of the Turkish armed forces was taken hostage.
There were scattered reports of gunfire, and Reuters cited a witness who said a military helicopter began shooting in Ankara. The wire service also reported that a military jet shot down a military helicopter over the city, possible police casualties, and a bomb that exploded at the Parliament building, according to state-run news agency Anadolu news.
The coup raised a host of critical questions at a time when Turkey is engaged in turmoil at home and with neighboring countries.
Roughly half of Syria's nearly 5 million refugees are in Turkey, straining the country's resources. Turkey has also been the launching point for many Syrian refugees heading to Europe. And Turkey's security forces have been involved in fighting with Kurdish separatists in the southeast.
The U.S. works with Turkey on multiple crises in the recent. To cite just one example, the U.S. military has been using Turkey's Incirlik Air Base for aircraft that are bombing the Islamic State in Syria.
The U.S. State Department used Twitter to urge American citizens in Turkey to contact family and friends to assure others of their safety, and to stay inside. A senior Defense Department official says operations at the U.S. air base in Incirlik — the base of operations for many strikes against the Islamic State — have not been affected.
Meanwhile, Turkish Prime Minister Binali Yildirim called the military actions in multiple cities an attempted coup. He told television channel NTV, "Some people illegally undertook an illegal action outside of the chain of command."
"The government elected by the people remains in charge. This government will only go when the people say so," he said.
Social media sites including Twitter and Facebook were down in Turkey for at least some portion of the evening, according to a tweet by the Internet watchdog group Turkey Blocks.
Reports on social media and in local press described tanks in the streets and military planes and helicopters overhead in the capital.
NTV showed images of tanks at Istanbul's Ataturk Airport, the scene of a terrorist attack that killed at least 42 people in June, and a pilot at the airport said all outbound flights had been canceled.
A spokesman for the FAA, Laura Brown, said in an email statement to NPR that any U.S.-bound flights from Istanbul that were in the air before the airport closed will be allowed to land in the U.S.
Dogan News reported that military vehicles blocked two major bridges over the Bosporus in Istanbul.
This is a breaking news story. We will update this post with further information as we have it.