• Armed forces who call themselves the "Peace Council" claimed they "fully seized control" of Turkey
• The Turkish chief of military staff is back in control, reports are surfacing.
• After a bizarre FaceTime interview, President Recep Tayyip Erdogan has landed in Istanbul.
• Soldiers have blocked entry to Ataturk Airport and stopped all flights.
• An F-16 has shot down a military helicopter used by "coup plotters".
A top Turkish official says the coup attempt within the country's military appears to have been unsuccessful.
President Recep Tayyip Erdogan is back in the country and has been seen live on television with cheering crowds.
The senior official told The Associated Press all government officials are in charge of their offices, but cautioned that the chief of military staff hasn't appeared in public yet.
The official requested anonymity because of the sensitivity of the issue.
It came after Turkish media reports cited MIT, the national intelligence agency, as saying the coup has been defeated.
The MIT website was not immediately accessible from Turkey. MIT spokesman Nuh Yilmaz said that Gen. Hulusi Akar, the military chief of staff, was back in control.
Yilmaz said "Gen. Akar is back on top of his duties". "Everything is returning to normal," he added.
Presidential Spokesman Ibrahim Kalin told NTV television: "The military commanders have made it clear that the coup plotters violated the chain of command... The people have shown that they stand in solidarity with democracy and the elected government."
A presidential source said a plane carrying Turkish president Recep Tayyip Erdogan had landed at Istanbul airport, Agence France-Presse reported.
Earlier, gunfire and explosions were heard on the streets of the Turkish capital following an attempted coup by the country's military.
Protesters called to the streets by Turkey's president were reportedly shot by the military, with CNN Turk reporting three wounded on the Bosphorus Bridge. TV footage showed people running for cover as shots rang out.
The situation appears to be rapidly deteriorating. Reuters reports tanks have opened fire near the Turkish parliament building, and Agence France-Presse reports a Turkish F-16 has shot down a Sikorsky helicopter carrying "coup plotters".
Meanwhile, the state-run Anadolu news agency reports 17 police officers have been killed in a helicopter attack on police special forces headquarters in outskirts of Ankara.
The Turkish military said on Friday (local time) that it had assumed power over Turkey, in what the prime minister has termed an illegal act.
"The power in the country has been seized in its entirety," said a military statement read on NTV television, without giving further details. The military's website was not immediately accessible.
It said the move had been made "in order to ensure and restore constitutional order, democracy, human rights and freedoms and let the supremacy law in the country prevail, to restore order which was disrupted".
"All our international agreements and commitments retain their validity. We hope our good relations will continue with all countries in the world."
The Turkish military group is calling itself the "Peace at Home Council".
Television pictures showed tanks deployed outside Ataturk airport in Istanbul. Reports said that flights into the airport had been halted.
In a bizarre Facetime interview broadcast on Turkish TV, president Recep Tayyip Erdoğan denounced the attempt by a "minority" inside the army. "I certainly believe that coup plotters will not succeed," Mr Erdogan told CNN Turk television.
"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."
Mr Erdogan said he was still president and Turkey's commander in chief, promising that plotters would pay a "very heavy price". A presidential source said Erdogan was in a secure location as per government protocol.
MSNBC reported Mr Erdogan was in an airplane that had been refused landing at Istanbul and was now trying to seek asylum in Germany, according to US defence officials.
It is still unclear who is in control of the country.
Shortly after Mr Erdogan's statement, a strong explosion was heard in the Turkish capital and there were reports of gunfire as thousands of people poured onto the streets.
Turkish social media users reported military helicopters had fired two missiles at the headquarters of the Turkish Radio and Television Corporation (TRT).
Presidential sources earlier told Agence France-Presse: "This is an attack against Turkish democracy. A group within the Armed Forces has made an attempt to overthrow the democratically elected government outside the chain of command.
"The statement made on behalf of the Armed Forces wasn't authorised by the military command. We urge the world to stand in solidarity with the Turkish people."
The state-run Anadolu news agency reports the country's top general has been taken hostage at the military headquarters in the capital Ankara after an attempt to bring down the government.
"General Hulusi Akar has been taken hostage by a group in the military who attempted an uprising," the agency said citing "credible sources".
However, Sky News reported the state broadcaster had been stormed by the military and staff have been asked to hand in their mobile phones.
Facebook, Twitter and YouTube have reportedly been restricted.
The Ministry of Foreign Affairs and Trade says it is monitoring the situation in Turkey as it develops.
"New Zealanders in Turkey are advised to stay at in their home or accommodation, monitor the media to stay informed of developments, let their family in New Zealand know they're safe and well and ensure they're registered on www.safetravel.govt.nz," a ministry spokesman said in a statement.
A message has been sent to all Kiwi SafeTravel registrants in Turkey providing this advice.
There are 202 New Zealanders registered on SafeTravel as currently being in Turkey.
Earlier, Turkey's prime minister said a group within Turkey's military had engaged in what appeared to be an attempted coup.
Binali Yildirim told NTV television: "It is correct that there was an attempt."
Mr Yildirim didn't provide details, but said Turkey would never allow any "initiative that would interrupt democracy".
"Those who are in this illegal act will pay the highest price," he added, saying it would not be correct to describe the move as a "coup".
Earlier, military jets were heard flying over the capital, Ankara, and there were reports of vehicles blocking two major bridges in Istanbul.
Media reports said ambulances were seen in front of the Turkey's military headquarters.
"We are focusing on the possibility of an attempt (coup)," Mr Yildirim said.
"There was an illegal act by a group within the military that was acting out of the chain of military command. Our people should know that we will not allow any activity that would harm democracy."
NTV is reporting that helicopters are also flying over headquarters in Ankara.
"There are certain groups who took the arms trusted to them by the state and pointed them toward state employees," Yildirim said. "We shall determine soon who they are. Our security forces have acted against these groups."
The Dogan news agency says one-way traffic on the Bosporus and Fatih Sultan Mehmet bridges were blocked. Video footage showed the bridge being blocked by military vehicles.
Turkish security forces on Friday partially shut down the two bridges across the Bosphorus Strait in Istanbul as military jets were heard flying low over Ankara, reports and AFP correspondents said.
The Bosphorus and Fatih bridges were closed by the gendarmerie - a branch of the Turkish military dedicated to internal security - for traffic travelling from Asia to Europe, NTV television said.
US Secretary of State John Kerry said he was still catching up with fast-moving events in Turkey, but he said that however events play out, he hoped that Turkey would be able to resolve the crisis while preserving peace, stability and a respect for "continuity."
Mr Kerry said while it would be "inappropriate" to comment on developments, he expressed hope that the key ally and strategically important member of the coalition fighting the Islamic State would remain at peace.
In a joint press conference with Mr Kerry, Russian Foreign Minister Sergei Lavrov called on Turkey to avoid all "bloodshed" as troops were on the streets of the country's major cities Friday amid reports of an attempted coup by the military.
Mr Lavrov said that "problems in Turkey need to be resolved in accordance with the constitution".
Turkey has a history of coups with governments ousted on three occasions in the last decades by full military coups.
However analysts had usually assumed that the ruling Justice and Development Party (AKP) of President Erdogan had good relations with the military.
United Nations Secretary-General Ban Ki-moon said in a statement he was following the fast-moving developments in Turkey closely and with concern.
He appealed for calm, non-violence and restraint.
"Preservation of fundamental rights, including freedom of speech and assembly, remain of vital importance."
He said military interference in the affairs of any state was unacceptable.
"It will be crucial to quickly and peacefully affirm civilian rule and constitutional order in accordance with principles of democracy."