Updated

Hamas (search) and other militant groups were on the verge of agreeing to halt attacks on Israelis, Palestinian officials said Monday, while Israel warned it may not accept what it considers a tactical cease-fire meant to give the militias time to regroup for more violence.

A U.S.-backed peace plan, the "road map" (search) to Palestinian statehood by 2005, has been hung up over the two sides' inability to end 33 months of fighting, with each saying, in effect, that the other must go first.

An agreement by Palestinian militias to suspend their armed uprising could be a major breakthrough and a way out. However, Israeli officials remained deeply suspicious, saying a truce is just a ploy by militants to win time to prepare for more shootings and bombings.

Early Tuesday, Israeli forces swept into the West Bank city of Hebron and arrested more than 100 Palestinians, the army said. The army said the raid, that comes just days after Israeli troops shot and killed Abdullah Kawasme, the Hamas leader in the city, targeted militants in the Hamas.

Troops also closed off the old city of Nablus and searched for terror suspects, the army said. Several suspected militants were arrested.

The terms of the emerging deal between Palestinian Prime Minister Mahmoud Abbas (search) and the militias were not clear. One Palestinian mediator said the truce will be open-ended and apply not only to Israel, but also the West Bank and Gaza Strip -- a key condition for Israel.

However, a leader of one of the armed groups said on condition of anonymity that Hamas will only accept a three-month truce. Leaders of the smaller Islamic Jihad group are trying to persuade activists to accept a limited deal, but are facing stiff opposition, he said.

Palestinian officials, including Foreign Minister Nabil Shaath and Cabinet Minister Yasser Abed Rabbo, were optimistic, saying they expect a positive response by the militias. A Hamas leader, Mahmoud Zahar, said the announcement would not come Monday -- contradicting assessments by Palestinian officials -- but said that "the decision will hopefully come very soon."

Hamas has repeatedly walked away from the Egyptian-brokered truce efforts, but the Islamic militant group is feeling the squeeze after the Iraq war. Washington has urged Arab nations to stop funding Hamas, Syria closed the offices of Palestinian militant groups and Israel threatened to assassinate Hamas leaders. Last week, Secretary of State Colin Powell called Hamas an "enemy of peace."

A Palestinian uprising leader, Marwan Barghouti, has also lent his prestige to the talks, writing cease-fire proposals from his Israeli prison cell and forwarding them to Khaled Mashal, a Hamas leader based in Syria, according to a source close to the negotiations.

Barghouti's final draft was delivered to Mashal this week, and the Hamas leader has promised to give his response to the Egyptian government quickly, according to the source. The document says the militias are willing to give Abbas a chance to negotiate an agreement with Israel.

Interviewed Monday by Israel TV, Egyptian Foreign Minister Ahmed Maher said Egypt is trying to persuade the militias to "put an end to their armed resistance during a (cease-fire), during which we will work for implementation of the road map." He said there were still some problems with Hamas.

Palestinian security minister Mohammed Dahlan told Israel TV's Channel 10 that the agreement would call for a halt to attacks against Israelis in the West Bank and Gaza as well as Israel.

The involvement of Barghouti would probably mean that another militia, the Al Aqsa Martyrs' Brigade, also would honor a truce, and that could make it easier for Hamas to accept. Barghouti is on trial by Israel for alleged involvement in attacks that killed 26 Israelis.

Hamas, the largest and deadliest group, has set the tone for the other armed factions.

However, Israeli officials said a Hamas-Abbas understanding might not necessarily be acceptable to them, noting that under the peace plan, the Palestinian Authority must disarm militias, not court them. At best, Israel would accept an internal Palestinian arrangement as a brief precursor to a crackdown, officials said.

Abbas has said he will not use force against the militants, for fear of civil war.

"The Palestinians must fight all the terror organizations," Israeli Defense Minister Shaul Mofaz said Monday. "Their dialogue with the terror organizations is their business."

A top Israeli security official said the truce talks give Hamas too much leverage. "It's unacceptable for the Palestinian Authority, Israel and the United States to agree to a situation in which a certain Hamas leader decides when progress (on the road map) will be made," said Maj. Gen. Amos Gilad. "It's an easy solution that will cost us in blood."

A key sticking point has been Israel's refusal to date to halt targeted killings of wanted Palestinians. Israel says it reserves the right to go after "ticking bombs," but uses a broad definition that includes not only assailants about to carry out attacks, but also those who send them. Over the weekend, Israeli troops killed a Hamas leader, Abdullah Kawasme, whom Israel blames for the deaths of 52 Israelis.

Hamas and the other militias want Israel to promise that it will halt all military strikes following a cease-fire. Egyptian mediators have tried to get an Israeli guarantee, and have asked the United States for help. Powell has said Israel has the right to stop "ticking bombs," but rejects Israel's broader definition.

Also Monday, Israeli and Palestinian security officials held more talks on the terms of an Israeli troop pullback in Gaza. The peace plan requires Israel to gradually withdraw to positions held before the outbreak of fighting as the Palestinians disarm the militias.

Once Israeli troops pull back, Palestinian security forces are expected to take over and prevent attacks on Israelis from those areas they reoccupy. Palestinian officials have said they don't want to assume security responsibility until they've reached a truce deal with Hamas.

Gilad said that after an Israeli withdrawal, Palestinian security forces would have a grace period of about a month, implying that there would be no Israeli military strikes during that time.