Israel called up reserve soldiers Thursday, as troops returned to five West Bank towns in response to two homicide bombings that killed 26 Israelis in two days. Yasser Arafat appealed to Palestinian militias to stop attacking Israeli civilians.

In the northern West Bank town of Jenin, Israeli forces rounded up about 2,500 Palestinian men and boys, about 1,000 of whom were released Thursday, Palestinians said. The Israeli military was checking on the figures. The sweeps in the town, a hotbed of Palestinian militancy, began early Wednesday.

Meanwhile, divisions were growing in Israel over Prime Minister Ariel Sharon's decision to gradually seize Palestinian areas and occupy them until terror attacks end. Defense Minister Binyamin Ben-Eliezer, leader of the moderate Labor Party, said he strongly opposes long-term reoccupation of Palestinian areas.

The back-to-back bombings in Jerusalem on Tuesday and Wednesday prompted President Bush to put his prescription for Palestinian statehood on hold, but he remained confident Mideast peace could be achieved. Bush repeatedly has demanded Arafat do more to stop terror attacks against Israelis.

Israeli military sources said one brigade -- about 1,200 soldiers -- was being called up for Israel's widening campaign, and that more troops may be drafted in the future. They would be deployed along the so-called Green Line, Israel's unmarked frontier before it captured the West Bank in the 1967 Mideast war. All homicide bombers of the past 21 months have come from the West Bank.

In the West Bank town of Ramallah, Arafat condemned attacks on Israeli civilians and said shootings and bombings "must be completely halted." Otherwise, he warned, the result might be "full Israeli occupation of our lands."

The statement was distributed Thursday by the official Palestinian news agency Wafa, but wasn't televised, though his aides initially said he would speak before the cameras for a wider reach.

White House press secretary Ari Fleischer said Bush is waiting to see how Arafat's latest denunciation of terrorism turned into action. "The progress the president is looking for is not rhetorical, it's meaningful and the president is waiting to see," Fleischer said.

Thursday's condemnation by Arafat was relatively mild. In December, Arafat said in a televised address that homicide bombings and all other "terrorist activities" against Israel must cease. He pledged to arrest militants who persisted with attacks. Thursday's statement didn't use the word terror, and Palestinians maintain they cannot carry out arrests while under Israeli siege.

Arafat said Thursday that Israel, through its military actions, is "preventing all our efforts" to end the violence. Arafat did not say how he would rein in the militias. Israel has accused him of doing nothing to stop attacks or even of encouraging them.

The Islamic militant group Hamas said it would not stop the bombings.

"If we have an effective weapon in our hands and the whole world is trying to take it off us, this kind of reaction shows it to be the most effective way," said Ismail Abu Shanab, a Hamas spokesman in the Gaza Strip.

Hamas claimed responsibility for an attack Tuesday on a Jerusalem bus that killed 19 Israelis, the worst in Jerusalem in six years.

Sharon, addressing an annual gathering of diaspora Jews at the three-day Zionist Congress in Jerusalem, said his visit to Tuesday's bombing scene revealed horrors beyond any the retired general had seen on the battlefield.

Terror attacks aren't new to Israel, he said, but "the difference is that this time, behind the acts of sabotage and murder, is a terrorist Palestinian Authority with the support of the international terror axis -- Tehran, Damascus, Baghdad and (alleged terror mastermind Osama) Bin Laden."

A bombing Wednesday at a Jerusalem bus stop killed seven Israelis, including a 59-year-old grandmother and her 5-year-old granddaughter. Arabic television channels reported conflicting responsibility claims, and it wasn't clear who was behind the blast.

The bomb wrecked the bus stop and left the wide street littered with personal belongings and body parts. Rescue workers covered an overturned baby carriage with black plastic sheeting.

Israel's reaction to the bombings has been a series of incursions and sweeps into West Bank towns -- and Sharon's declaration that Palestinian areas would be taken over for longer periods in reaction to attacks.

By Thursday troops were in control of Jenin and Qalqiliya, setting up command posts in the towns and enforcing curfews. After two days inside Qalqiliya, the tanks pulled back to the edges of the town. Tanks also rolled into Tulkarem, just inside the West Bank, and an adjacent refugee camp.

Also Thursday, troops moved into Beitunia, a suburb of Ramallah, and searched for suspects. A military statement said soldiers would remain in the two locations "until the mission's goals are accomplished." Beitunia residents were ordered over loudspeakers to stay in their homes. Three armored personnel carriers, a tank and a military jeep were parked outside a five-floor building, one of three positions taken over by the Israeli army. Building residents peered out from their windows.

Palestinian hospital and security officials said a pregnant Palestinian woman, Sahar Hindi, 27, died after being shot in the chest during an exchange of gunfire in Qalqiliya. Israeli military officials said a woman had been hit in a gunfire exchange, but further details weren't yet clear.

Israeli helicopters and warplanes pounded Palestinian buildings in the Gaza Strip, wounding 13 Palestinians.

Sharon never explained publicly how far Israel would go in the planned reoccupation of Palestinian areas -- whether troops would seize entire towns or set up new positions on the outskirts of population centers.