Federal Liberal leadership hopeful Michael Ignatieff's latest comments on the Israeli air strike in Qana have cost him a key campaign member.

Susan Kadis, a Thornhill MP and his Toronto campaign co-chair, withdrew her support Wednesday after Ignatieff accused Israel in a televised interview on Sunday of committing a "war crime" in the July 30 bombing in Lebanon.

"Michael is an intelligent person and I would think that he would have a better handle on the Middle East given his years of experience on human rights and international law," Kadis said in a written statement.

Ignatieff was trying to clarify previous controversial remarks about Qana on Radio-Canada program Tout le monde en parle on Sunday.

After the air strike that killed more than two dozen people, Ignatieff told the Toronto Star in August that civilian deaths were inevitable in the conflict between Israel and Hezbollah.

"This is the kind of dirty war you're in when you have to do this and I'm not losing sleep about that," he said.

Ignatieff soon expressed regret over those remarks and sought to explain what he should have said on Sunday.

"I was a professor of human rights and I am also a professor of the laws of war and what happened in Qana was a war crime and I should have said that," he said.

'Very troubling' comments

Kadis called the latest comments "very troubling"

Ignatieff released a statement indicating he regretted the decision Kadis made.

The statement also included assertions that "the denial of Israel's right to exist is unconscionable and must stop" and that the country where he said he has lived and taught has "the unequivocal right to defend itself against unprovoked attacks."

He stopped short of calling the Qana attack a war crime.

"Qana was a terrible human tragedy where innocent civilians died in a conflict that saw unjustified tragedies on all sides," he said. 

Ignatieff said at a late afternoon news conference he still considered Kadis a close friend and respected colleague.