In pictures: The Attempted coup in Turkey
The group in Turkey said it had taken control over the country, with troops deployed at main points in Istanbul, including the Bosphorus Bridge.
A declaration which was made public on Turkish TV said a peace council controlled the country and was imposing a martial law amid curfew.
President Recep Tayyip Erdogan told CNN Turk by mobile phone the act was by a “parallel structure” that would bring the essential answer.
Erdogan said he would defeat the revolution by a small minority and insisted Turkish people to take to the streets and oppose the uprising.
Turkish President said, “I urge the Turkish people to convene at public squares and airports. I never believed in a power higher than the power of the people.”
Several Erdogan supporters turned out on Istanbul’s central Taksim Square, with reports of deadly clashes and gunfire.
Gunshots and explosions were even reported in Turkish cities, including reports of at least two explosions at a parliament building in Ankara.
The world leaders called for an end to violence in Turkey, with the US saying the democratically chosen government in the country should be respected.
Images and videos posted on social media showed casualties lying in the streets as people in the streets of Ankara took cover from gunfire.
A huge number of people also demonstrated outside Ataturk international airport, in Istanbul.
Later, a Turkish TV showed President Erdogan arriving at the Ataturk airport, where he spoke to media in a press conference.