"It's important for us to get some kind of ceasefire now. I think this idea of an international force needs to be fleshed out," Clinton said at a speech in Canada's eastern port city of Halifax on Wednesday.

Clinton said that even though Lebanese militia Hezbollah was keeping the conflict going, as it "attacks with rockets, then hides among civilians," Israel is also going too far in its response.

"No matter how measured the response is, if you go after them, you're going to kill innocent people," he said, adding, "I understand why (Israel) wanted to degrade their military capacity, but I question whether it was worth it to wreck the airport, because the airport was the symbol of the new Lebanon."

Clinton also said NATO was probably the only international group with the military muscle capable of fielding a peacekeeping force.

Clinton is in Canada this week to talk about bilateral relations. The 42nd president of the United States has been to Canada 20 times since he left the Oval Office in 2000, mostly for speaking engagements.