Israel faces an "earthquake" of revenge for killing Hamas founder Sheik Ahmed Yassin (search), the militant group's Syrian-based leader said Saturday.

Yassin, a quadriplegic, was killed in an Israeli missile attack Monday as he was being wheeled out of a Gaza (search) mosque. Israel has accused him of planning attacks that have killed hundreds of Israelis.

"I say with absolute certainty that the assassination of Sheik Ahmed Yassin will cause an earthquake to the Zionists," Khaled Mashaal (search) told Dubai-based TV station Al-Arabiya. He said the revenge "will spare no targets."

Mashaal, who heads Hamas' political bureau, also criticized the United States for vetoing a U.N. Security Council (searchresolution Friday condemning Israel for killing Yassin, but said his group will not attack U.S. targets in the Middle East.

He warned, however, that "America's bias" toward Israel and its occupation of Iraq were creating enemies for it throughout the Arab and Islamic worlds.

"Hamas' ... battle is inside Palestine and against the Zionist occupation ... but I cannot predict what the reaction of Arab and Islamic masses might be," he said.

The United States lists Hamas (search) as a terrorist organization.

Mashaal also urged Arab leaders not to revive a peace initiative with the Jewish state, saying "peace with Israel has become an illusion."

Some Arab states were hoping to revive a 2002 peace initiative toward Israel at an Arab League summit, but the meeting collapsed Saturday two days before it was to start, in part because of differences over the proposal.

Sheik Hassan Nasrallah, leader of Lebanon-based Hezbollah, told a rally in Beirut his group was closing ranks with Hamas in the battle against the Jewish state. Hezbollah has launched numerous attacks against Israeli forces.

He taunted Israel, whose army chief suggested after Yassin's death that Nasrallah and Palestinian Authority leader Yasser Arafat could be next on Israel's hit list.

"The talk about assassinations does not frighten us," Nasrallah said. "I tell the Israelis that we are here in Lebanon waiting for them."