Tens of thousands of people in the Hamas-ruled Gaza Strip on Tuesday rallied against the Mideast peace conference under way in the U.S while the group's top leader in Gaza insisted the summit is "doomed to failure."

The comments by Ismail Haniyeh, leader of the Hamas government in Gaza, came as protesters began filling a huge square in Gaza City, chanting "Death to America" and "Death to Israel" and calling Palestinian President Mahmoud Abbas a "collaborator" for attending the gathering at Annapolis, Md.

Smaller demonstrations were held in Abbas' West Bank stronghold, including a protest that was violently broken up by police beating people with sticks and firing tear gas.

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In new violence, Israeli troops fatally shot two Hamas militants in separate incidents early Tuesday in the Gaza Strip, the army and Islamic group said. On Monday, four Palestinians were killed by Israeli troops in Gaza.

"Annapolis is a disaster for us," said Amina Hasanat, a 37-year-old mother of eight who demonstrated in a women-only section of the Gaza City rally. Dressed in a black robe and black and green headband, she predicted the conference would end in failure. "This will be an advantage for the resistance," she said.

Gaza's Hamas rulers have been staging daily demonstrations against the U.S.-hosted conference, restating their commitment to Israel's destruction and promising to reject any decisions that come out of Annapolis. The criticism has grown increasingly vitriolic, with one Hamas leader on Monday calling Abbas a "traitor."

Polls show that a majority of both Palestinians and Israelis favor a negotiated settlement to the conflict. However, a majority on each side is also skeptical that the current peace push will bear fruit.

Hamas violently seized control of Gaza last June after routing forces loyal to Abbas, and the president's lack of control of Gaza has raised questions about his ability to carry out a future peace deal. Israeli Prime Minister Ehud Olmert has said he will not implement a peace agreement without a halt to militant attacks emanating from Gaza.

In his speech, Haniyeh said his group would not disarm.

"We will stand firmly in the face of policies that attack the will of our people, our factions and our weapons of resistance," Haniyeh said. "We reaffirm the legitimacy of resistance and support it as a natural right."

Haniyeh also expressed dismay over the participation of 16 Arab nations — including Saudi Arabia and Syria, a key Hamas patron, at the U.S. summit.

He said the Arab masses "will reject ... any concessions to the Zionist enemy."

"We are sure that the Annapolis conference will not change the reality of history and geography," he added. "Any conference that goes beyond this reality is doomed to failure."

After Haniyeh's speech, the Gaza protest gained strength, beginning with several thousand pro-Hamas university students and quickly growing into tens of thousands of people.

"History will have no mercy on you," the crowd shouted in a reference to Abbas.

Smaller demonstrations against Annapolis took place in the West Bank despite a ban issued by Abbas.

About 300 protesters, many of them women, gathered in the West Bank town of Ramallah in defiance of the ban. "Oh Abbas ... this homeland is not for sale," they chanted.

About 50 uniformed security officers rushed toward the crowd, beating protesters with sticks and dispersing them with tear gas. There were no reports of injuries, though protesters said four people were arrested.