ANKARA - After years of tension, a handshake between Turkish President Tayyip Erdogan and Egypt's President Abdel Fattah al-Sisi last week opened the door to a flurry of back-door diplomacy between intelligence officials, two sources told Reuters.

Intelligence delegations from the two countries met in Egypt at the weekend, said a regional source with knowledge of the matter. The second source, a senior Turkish official, said "significant" discussions had begun between them, and Turkey and Egypt are set to begin talks on military, political and commercial issues including energy projects.

Turkish officials did not comment when asked about the meeting in Egypt. Egypt's foreign ministry did not immediately respond to a request for comment.

(Reporting by Daren Butler; Editing by Jonathan Spicer)