Updated

Israel's defense minister says the Syrian president has lost his legitimacy, and his fall would be "very positive."

Israeli Defense Minister Ehud Barak says the exit of Syrian President Bashar Assad would weaken Iranian influence in the region. He says anti-Israel Iranian proxies in Lebanon and Gaza would suffer if Assad is overthrown.

"The toppling of Assad will be ... a major blow to Iran," Barak told CNN. "It will be very positive event."

Israel considers Iran its most serious threat. Iran and Syria are close allies.

Barak said Thursday the world is not doing enough to force Assad out.

The U.S. called Thursday for tougher measures to hold Syria to a cease-fire meant to end its bloody 13-month crackdown on opponents.