Undercover Israeli soldiers fatally shot a Hamas activist in the Gaza Strip early Tuesday after he threw bricks at them from a roof and fled when they tried to arrest him, the army said.

Yassin al-Agha hid on the roof of a building in the Khan Younis refugee camp when troops conducted searches there for suspected militants, the army said in a statement. When soldiers tried to arrest al-Agha, he fled and soldiers shot him, the army said.

In searches carried out after al-Agha's death, soldiers found a bag with pipe bombs and an automatic weapon, the army said. The statement did not say of what al-Agha was suspected.

Later, about a dozen tanks and a bulldozer re-entered the camp and arrested three Palestinians, witnesses said. A 35-year-old man whose two brothers were among those arrested was beaten by soldiers, Palestinian police said. The injured man was taken to the hospital with two broken legs, hospital officials said.

The army had no immediate comment on the beating allegations.

Al-Agha was the third Palestinian killed in 24 hours, with Israeli troops continuously carrying out searches in West Bank and Gaza Strip towns and cities. A Palestinian woman and a mentally handicapped Palestinian were killed Monday by army fire in the West Bank.

Israel has reoccupied every major Palestinian town or city in the West Bank, except for Jericho, in what it says is an attempt to prevent suicide bombings and other attacks against Israelis.

Also in the Gaza Strip, Israeli soldiers fired late Monday on a U.N. bus carrying Palestinian students to a technical university, said officials in the United Nations Reliefs and Works Agency, or UNRWA. A 20-year-old was moderately wounded, Palestinian hospital officials said.

Tensions between UNRWA and Israel have been high since soldiers shot and killed one of the agency's British employees, Iain Hook, on Nov. 22 during a gunbattle with armed Palestinians in the Gaza Strip. The army said its soldiers mistook a cellphone Hook was using for a weapon and that gunmen had entered the walled UN compound. UNRWA denies that gunmen had entered the compound.

In Israel, preliminary results in a Labor Party primary vote for parliamentary candidates in Jan. 28 general elections indicated members had pushed out one of its most dovish members, Yossi Beilin, and topped its list with former generals.

With more than 50 percent of the primary votes counted, it appeared that Beilin, Labor's most outspoken supporter of concessions to the Palestinians and an architect of the interim peace accords, placed too low on the list to get a seat in parliament.

Polls indicate Labor will lose about six of its 26 seats in the 120-member parliament.The first three spots are reserved for the party's dovish new chairman, Amram Mitzna, as well as former Defense Minister Binyamin Ben-Eliezer and Shimon Peres.

Matan Vilnai, a former general and an outspoken supporter of Mitzna, came in first in the primary vote. A former chief of the Mossad spy service, Danny Yatom, also made the top 10, almost guaranteeing him a seat in parliament.

Polls predict Prime Minister Ariel Sharon's Likud party will trounce Labor in the election. Sharon on Monday called on Labor to join his coalition should he win the election.