Istanbul: The security of the Russia-US talks in Istanbul is ensured at a high level, and Ankara does not know how long they will take, a Turkish diplomatic source told RIA Novosti on Thursday.

According to Namibia Press Agency, the source confirmed, "It is provided at a high level," in response to a request to comment on the security measures taken by Ankara for the negotiation process.

The Turkish side does not know how long the negotiations will take, the source said. "This [Istanbul as venue of the talks] has been the choice of the parties themselves," the source added, emphasizing that the idea to change the venue of the talks to a different city was not discussed.