President Bashar Assad said Thursday his country will cooperate with a U.N. investigation implicating the military in the killing of a Lebanese politician, but he warned that such cooperation would stop if Syria was going to be harmed.

In Paris, French President Jacques Chirac warned Syria it could face sanctions if it refused to cooperate with the ongoing probe into the February assassination of former Lebanese Prime Minister Rafik Hariri. Assad, while maintaining Syria's innocence during a speech at Damascus University, also disclosed that a U.N. investigator has rejected Syria's conditions for cooperating with investigators.

"We will play their game" and cooperate, Assad said. But, he warned, that cooperation will "stop when Syria is going to be harmed."

Syria has come under intense pressure from the United States and the United Nations since Hariri and 20 others were killed by a car bomb. Chirac said Thursday the international community "will have move to another stage, which is sanctions" if Assad "persists in not wanting to listen or understand," Chirac said.

"It is not conceivable, admissible, acceptable for the international community ... that Syria refuses to cooperate," Chirac said.

A U.N. Security Council resolution has demanded that Syria cooperate with investigators. The U.N. commission led by German Detlev Mehlis wants to question six Syrian officials in Lebanon.

Assad said Thursday that Mehlis had refused Syria's offers to have the officers questioned on Syrian territory — even in U.N. offices there — or at the Arab League headquarters in Cairo, Egypt, in cooperation with Egypt.

Mehlis left Beirut, Lebanon, on Thursday for Germany, Beirut airport officials said.

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."

"Syria is innocent in the absolute sense," Assad said in the wide-ranging and hard-line speech. "Syria is not involved at the government level or at the individual level. The problem is merely a political one in the context of events."