Israel pulled out of two dozen small West Bank towns and villages Thursday, but swept into others and rounded up more Palestinian men despite U.S. calls and international pressure to end the 2-week-old campaign to root out militants.

Israel's army says 4,185 Palestinians have been detained in the operation — nearly half of them in the past two days as fighters in the key northern West Bank cities of Jenin and Nablus, their numbers depleted in battle, ran out of ammunition and surrendered.

Among those in custody were 121 Palestinians who had been on Israel's wanted list, the army said.

Secretary of State Colin Powell arrived in Israel in the evening and was expected to meet with both Israeli Prime Minister Ariel Sharon and Palestinian leader Yasser Arafat, who has been kept a virtual prisoner by Israel in his besieged compound in Ramallah.

On Thursday, Sharon acknowledged the fighting was causing the United States difficulties, but refused to call a halt to the incursion.

In Gaza, an armed Palestinian went through the Erez crossing into Israel early Friday and opened fire, wounding four Israelis — one seriously — and three Palestinians before he was shot and killed, the Israeli military said. Israel Radio and Army Radio reported. The military had no immediate comment.

There has been rising anti-American sentiment throughout the Arab world in response to Israel's offensive, launched two weeks ago to crush Palestinian militias after a series of deadly attacks on Israeli civilians.

"They [the Americans] have problems in the region, that's true, but I informed them that our activity will continue — and it will continue," Sharon said.

The United States, along with the United Nations and European leaders, has demanded an immediate Israeli pullout from the West Bank. Powell was visiting the region in an attempt to secure a cease-fire and restart peace talks.

In what appeared to be a gesture ahead of Powell's arrival, Israeli forces withdrew from about two dozen small towns and villages. But in raids early Thursday, they entered the West Bank towns of Dahariyah and Bir Zeit and the Ein Beit Hilmeh refugee camp. Later, they pulled out of Bir Zeit after detaining about 300 people, mainly students in the university town.

Israeli troops invaded Kalil near Nablus, making arrests before leaving, the military said in a statement Friday. Also, the statement said, "activities in Jenin, Nablus, Ramallah, Bethlehem, Dura and Dahariyah, south of Hebron, continue."

The White House raised no objection to the pace of Israel's response to President Bush's pleas. "The withdrawals he called for are continuing," White House spokesman Ari Fleischer said.

In the Jenin refugee camp, scene of the deadliest fighting during the offensive, three dozen armed men, apparently the last holdouts, surrendered to Israeli troops Thursday.

The battle in Nablus ended before dawn Wednesday, when an estimated 100 gunmen — hungry, exhausted and nearly out of ammunition — walked out of an Old City mosque.

Brig. Gen. Eyal Schlein, the Israeli army's Jenin division commander, told The Associated Press on Thursday night that occasional shooting persists in Jenin "and sometimes more than that."

"Many of the most wanted have been captured or killed, or were wounded and captured," he said. "The area is messy. There are many explosives, booby-traps. ... But overall, most of what we were looking for, we found."

Reporters touring the Jenin camp, which had been off limits to journalists during eight days of combat, saw widespread devastation from army bulldozers that had sheared the front walls off homes. But no bodies were seen in the streets Thursday.

Dr. Hussam Sherkawi, director of emergency services in the West Bank, said at least 140 Palestinians have been killed during the Israeli offensive. But he said it was impossible to verify death toll estimates because rescue services had not been permitted to enter the Jenin camp.

An army spokesman, Lt. Col. Olivier Rafowicz, estimated 100 Palestinians had been killed in fighting in Jenin. He denied persistent rumors the army had dug mass graves and said Israelis hadn't removed any bodies.

Twenty-eight Israeli soldiers have died in the military campaign, all but five of them in Jenin.

On Thursday, Israeli troops in the Jenin camp confiscated footage filmed by an Associated Press Television News cameraman.

Video footage obtained Thursday by APTN showed Arafat during recent meetings in his Ramallah compound. Arafat's pistol was visible at his waist as he met Wednesday with aides, some looking weary and unshaven. He softly read a translation of an Israeli Cabinet statement affirming continuation of the military operation. In another room, bullet holes scarred a wall, and a door and metal cabinet were propped up to block a window.

In Bethlehem, Israeli forces in armored personnel carriers circled the Church of the Nativity compound that has been the site of an extended standoff between soldiers and about 200 armed Palestinians. A ring of tanks controlled access from all sides. Black smoke wafted up near the compound; witnesses said the army had blown up some cars in the area.

A U.N. convoy distributed food to a Bethlehem refugee camp and to families in the city, which has been under nearly constant curfew since the church standoff began April 2. Troops patrolled streets and blew open doors to shops and homes, especially in the Old City, as they searched for militants.

"There is a lack of food and a lack of medicine, but the most important thing there is a lack of is freedom. I don't know when this crisis will find an end," said Tony Maria, a 45-year-old father of three looking off from his balcony at the patrolling tanks.

In other developments:

— An Israeli government official said the government had agreed to allow Egyptian Foreign Minister Ahmed Maher to visit Arafat. Maher said he would visit Arafat "when the time is right."

— Israeli tanks briefly re-entered the West Bank town of Tulkarem, where troops arrested a 24-year-old Palestinian woman who, according the Israeli military, was suspected of planning a suicide attack.

— A senior Israeli military official, speaking on condition of anonymity, said an Armenian monk seriously wounded in the Church of the Nativity compound was apparently shot by an Israeli soldier.

— In Tamoun village near Nablus, a Palestinian woman was killed and her husband and 2-year-old son injured by an explosion in their house, hospital officials said. The husband, who lost both hands, was apparently handling the explosive when it detonated.

— A Palestinian suspected of collaborating with Israel was killed in Khan Younis, Palestinian security officials in the Gaza Strip said.