A group within Turkey’s military has engaged in what appeared to be an attempted coup, the prime minister said, with military jets flying over the capital and reports of vehicles blocking two major bridges in Istanbul.

Prime Minister Binali Yildirim told private NTV television: “it is correct that there was an attempt,” when asked if there was a coup.

Yildirim didn’t provide details, but said Turkey would never allow any “initiative that would interrupt democracy.”

“We are focusing on the possibility of an attempt (coup),” 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.”

Earlier, military jets were heard flying over the capital, Ankara. Media reports said ambulances were seen in front of the Turkish military headquarters. 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.”

One-way traffic on the Bosporus and Fatih Sultan Mehmet bridges were blocked. Video footage showed the bridge being blocked by military vehicles.