An army group in Turkey says it has taken control of the country, with bridges closed in Istanbul and aircraft flying low over Ankara.
PM Binali Yildirim earlier denounced an "illegal action" by a military "group", stressing it was not a coup. He said that the government remained in charge.
Report: Turkish military releases statement, saying armed forces have 'fully seized control' of the country.
— The Associated Press (@AP) July 15, 2016
Traffic has been stopped from crossing both the Bosphorus and Fatih Sultan Mehmet bridges in Istanbul.
There are reports of gunshots in the capital Ankara.
BREAKING: Secretary of State John Kerry says he hopes for stability, peace, continuity in Turkey as coup apparently under way.
— The Associated Press (@AP) July 15, 2016
Gunfire was also heard outside Istanbul police HQ and tanks are said to be stationed outside Istanbul airport. All flights are cancelled.
CNN Turk reported that President Recep Tayyip Erdogan was "safe" but did not elaborate.
A statement from the military group read out on NTV television said: "The power in the country has been seized in its entirety." Who represents the group remains uncertain.
A Turkish presidential source told Reuters that the statement was not authorised by the military command.
Mr Yildirim told NTV by telephone: "We are working on the possibility of an attempt. We will not allow this attempt.