Updated

JERUSALEM -- Israel's defense minister has expressed regret for the deaths of pro-Palestinian activists in a clash with navy commandos. But he has blamed the violence on organizers of a flotilla carrying aid to the blockaded Gaza Strip.

Speaking at a Monday news conference in Tel Aviv, Ehud Barak called the aid flotilla a "political provocation" by anti-Israel forces. He said the sponsors of the flotilla are violent.

Israel's military chief, Lt. Gen. Gabi Ashkenazi, said soldiers were forced by violent activists to respond with live fire.

At least 10 activists were killed in Monday morning's clash in international waters of Israel's Mediterranean coast.