The Israeli military is willing to suspend operations against Palestinian militants if they call off attacks, Israel's defense minister said Sunday, signaling a shift that could help pave the way for a cease-fire after more than four years of fighting.

Defense Minister Shaul Mofaz (search) also said Palestinian leader Mahmoud Abbas (search) has received assurances from at least two militant groups, Hamas (search) and Islamic Jihad, that they will halt attacks on Israel for at least a month.

During this time, a more detailed agreement, including the terms of possible political participation of the opposition groups, would be negotiated, Mofaz said. He did not say how he learned about the cease-fire.

Hamas officials gave conflicting responses to the reported truce. A senior official, speaking on condition of anonymity, said the group has agreed to a test period of 30 days. If Israel does not carry out military operations during this period, Hamas will consider an open-ended cease-fire, the official said.

But a second Hamas official, Sami Abu Zuhri, denied any deal had been reached. "The things that Mofaz says, that we've reached a cease-fire, is not true. We're still studying the subject," he said, adding that a final deal would depend on Israel halting its attacks on the group.

Mofaz spoke a day after a key group of militants, the Al Aqsa Martyrs' Brigades, said it is ready for a truce, provided Israel halts military operations, including raids and targeted killings of wanted men. Al Aqsa has ties to Abbas' ruling Fatah movement.

Fatah officials could not immediately be reached for comment on the truce reports.

In the past Israel has refused to promise militants amnesty, despite requests from Egyptian mediators who say such a promise is crucial to their efforts to arrange a truce.

However in remarks to Israel Radio on Sunday, Mofaz said a halt in Palestinian attacks could lead the Israeli military to hold back. Israel is giving the new Palestinian leader — also known as Abu Mazen — a chance to complete his deal, Mofaz said. "As long as there is quiet, there is no reason why we should act, certainly not while Abu Mazen is taking his first steps," Mofaz said.

Mofaz said a deal is emerging between Abbas and the militants. "As far as we know, there is an agreement between Abu Mazen, Islamic Jihad and Hamas, a cease-fire for a certain period ... something like a month," Mofaz said. During that time, negotiations will continue toward a broader agreement on power-sharing and a joint political platform.

Participants in the talks have said a plan under consideration calls for the establishment of a Palestinian state in the West Bank, Gaza Strip and east Jerusalem, the areas Israel captured in the 1967 Mideast war. Hamas in the past has called for Israel's destruction, and acceptance of the plan would mean a fundamental change in the militants' position.

Hassan Yousef, the Hamas leader in the West Bank, said his group wants assurances from Abbas that he will bring Hamas members into Palestinian Authority positions, including the security forces. Hamas also wants elections in the Fatah-dominated PLO, the body that represents Palestinians everywhere, including the diaspora.

Mofaz said he was cautiously optimistic after the recent lull in violence and the deployment of 3,000 Palestinian police in northern Gaza over the weekend. He said that Israel is willing to withdraw from Palestinian towns and cities as soon as the Palestinians are ready to take control there.

Such a pullback, along with Israel's planned withdrawal from the Gaza Strip and the dismantling of four West Bank settlements, could create a new reality in 2005, he said.

In the West Bank city of Nablus, meanwhile, Israeli troops discovered a weapons lab containing 55 pounds of explosives, 40 gallons of chemicals and three explosives belts of the kind used by suicide bombers. The city has been a center of militant activity during four years of fighting.