After US Pilot Erred in Bombing Canadians,
President Bush telephoned Canadian Prime Minister Jean Chretien to convey condolences. Defense Secretary Donald Rumsfeld said,

"On behalf of the Department of Defense, I want to express my deep regret and sadness over the tragic accident in Afghanistan that killed and wounded a number of Canadian troops. "Our thoughts and prayers go out to them, their comrades and their families."

The fact that the US didn't apologize for what the government acknowledges actually happened is interesting in light of the US's unwillingness to apologize to the Chinese for something that was the fault of the Chinese. In other words, there was absolutely no reason for the US to aplogize to the Chinese.