The Palestinian security chief called for an end to suicide bombings against Israel, denouncing "murders for no reason," in an interview published Friday in an Israeli newspaper.

Israel's chief of police, however, warned that despite relative calm for the past three weeks, Palestinian militants are still trying to carry out attacks against Israelis. Also, the militant group Hamas pledged revenge for Israel's killing of four civilians in Gaza on Thursday.

Interviewed in the Yediot Ahronot daily, the Palestinian security chief, Interior Minister Abdel Razak Yehiyeh, said he told leaders of Palestinian groups, including Hamas and Islamic Jihad, to "stop the suicide bombings, stop the murders for no reason."

An aide to Yehiyeh confirmed that he had talked to the Israeli newspaper.

Yehiyeh, a retired general, was appointed interior minister in June in a Cabinet reshuffle, taking charge of Palestinian security forces. Palestinian leader Yasser Arafat had held the post until then.

In the interview, Yehiyeh said that "suicide attacks are contrary to the Palestinian tradition, against international law and harm the Palestinian people."

"Children were exploited for these attacks," Yehiyeh said. Several of the bombers were teen-agers.

During nearly two years of Palestinian-Israeli fighting, more than 250 Israelis have been killed in more than 70 suicide attacks, most of them in Israeli cities.

Arafat has on occasion spoken out against suicide bombings, though Israel says he has encouraged violence against Israeli civilians.

Palestinian intellectuals recently published a statement calling for a halt to bombings, saying they harm the Palestinian cause. However, polls indicate that a majority of Palestinians continue to support attacks on Israelis as a way of settling scores for Israeli military strikes against them.

Israel has imposed restrictions and travel bans in the West Bank, crippling the economy. It says the measures are necessary to keep bombers out of Israel.

Yehiyeh has been meeting with leaders of Palestinian groups to persuade them to accept a plan he worked out with Israeli Defense Minister Binyamin Ben-Eliezer aimed at easing crippling Israeli restrictions in the West Bank.

Under the plan, Israel was to turn security enforcement in the West Bank town of Bethlehem and the Gaza Strip over to the Palestinians as a test case. If the Palestinians prevented terror attacks, Israel pledged to loosen its grip on the rest of the West Bank. The Bethlehem handover took place Aug. 20, but there has been no movement in Gaza, and the two sides blame each other for the delay.

Hamas and other extremist groups rejected the plan and pledged to continue their attacks against Israel. Militants threatened revenge after an Israeli tank fired shells at a Bedouin encampment near a Jewish settlement in Gaza early Thursday, killing a mother, two of her sons and another relative.

"We will retaliate against the criminals, civilian and non-civilian," said Hamas spokesman Mahmoud Zahar, adding that the military wing of the Islamic group "will do its best to take the proper retaliation to stop more killing on the Palestinian side."

Israel expressed regret for the loss of civilian life. Palestinian Health Minister Riad Zanoun said Israelis fired flechette shells, which spread lethal darts around a large area. Zanoun noted that flechette shells are illegal under international law.

Israeli media said military sources confirmed that flechettes were used.

Israeli Police Commissioner Shlomo Aharonishki warned that the three-week lull in Palestinian attacks does not mean the Palestinians have changed their tactics. In an interview published Friday, he told the Maariv daily that the lull was a result of successful Israeli anti-terror operations.

"I don't see fatigue among the Palestinians, and I don't perceive less motivation to carry out terror attacks," he said.

In the West Bank city of Nablus, Israeli troops left the main government building after blowing up the part where the governor, Mahmoud Aloul, had his office. Aloul said there were no explosives stored in the building, which was almost empty because of an Israeli army curfew in the city.

The Israeli army refused to comment, and military sources, speaking on condition of anonymity, would say only that soldiers searched the building for explosives and suspects as part of the Israeli military's routine operations in the city.