DAMASCUS, Syria — Syria's president Thursday reiterated his country's innocence in the killing of a prominent Lebanese politician. He pledged to cooperate — for now — with a U.N. investigation that implicated Syrian military officers but warned such cooperation will stop "when Syria is going to be harmed."

President Bashar Assad also disclosed that a U.N. investigator has turned down Syria's conditions set on the investigation cooperation.

"We will play their game" and cooperate, Assad said in a speech at Damascus University. But, he warned, the country will "stop when Syria is going to be harmed."

Syria has come under intense pressure from the United States and the United Nations since the February assassination of Rafik Hariri, a former prime minister of Lebanon.

A U.N. Security Council resolution has demanded that Syria cooperate with an international probe into the assassination. The U.N. commission, led by German investigator Detlev Mehlis, wants to question six Syrian officials in Lebanon.

Assad disclosed in his speech that Mehlis had refused Syria's offers to hold the questioning of the officers on Syrian territory — even in U.N. offices there — or at the Arab League headquarters in Cairo, Egypt, in cooperation with Egypt.

Assad said the latest events confirm that "no matter what we did and how much we cooperate, the result will be that Syria did not cooperate."