The Israeli military killed a senior Hamas commander in the southern Gaza Strip Sunday and continued massing troops and tanks outside the area. Later in the day, the radical Islamic group fired rockets into the largest Jewish settlement in Gaza, damaging at least one house and wounding six Israelis inside.

The exchange came as an Egyptian delegation arrived here in a bid to salvage a five-month-old truce between Israel and the Palestinians and calm factional tensions between Hamas, known formally as the Islamic Resistance Movement, and the Palestinian Authority. The authority has sought in recent days to prevent the Hamas military wing from firing rockets on Israeli towns and settlements. But the talks with the Egyptians failed to win an explicit Hamas pledge to abide by the truce, which appears to have collapsed, at least for the moment.

"You can't ask the Palestinian factions to sit on the side while the Israelis attack the Palestinian people," said Saed Sayam, a Hamas political leader, after a three-hour meeting with the delegation at a beachside hotel here. "Up to this moment we are committed to the truce. But we have the right to respond to the aggression of the other side."

The possibility of a large Israeli military operation, threatened for days, remained uncertain.

The Israeli military said an army sniper killed Sayid Sayem, identified as a senior Hamas military commander in Khan Younis, Sunday morning. Sayem, 31, was shot through the neck on the roof of his house.

Israel had suspended its policy of assassinating Palestinian militant leaders as part of a temporary truce that Prime Minister Ariel Sharon and Palestinian leader Mahmoud Abbas announced in February. The agreement had brought a period of calm, but the truce has been severely strained by violence in recent days.

A few hours after Tziam's death, Hamas fired several rockets into the Gaza settlement of Neve Dekalim south of here, wounding four Israelis seriously and two others lightly. Several rockets also landed on the Israeli city of Sderot, although no casualties were reported.

At the weekly cabinet meeting in Jerusalem, Sharon gave the military wide leeway to stop the Hamas rocket attacks, which have threatened his plan to evacuate all 21 Jewish settlements from Gaza and four in the northern West Bank next month.

"We are greatly interested in reaching a diplomatic settlement," Sharon said. "But it is totally clear that this is impossible while such terrorism runs amok along our borders."

Israeli military officials said troops remained outside Gaza despite several days of attacks from Hamas and Islamic Jihad, a smaller organization that also refuses to recognize Israel's right to exist. The officials said they wanted to give Abbas a chance to confront the groups himself.

Palestinian security forces, which clashed Friday with Hamas fighters shooting rockets into Israel, moved in large units through the streets here Sunday, removing green Hamas banners. Sayam, the Hamas official, said Hamas and the Palestinian Authority, dominated by the secular Fatah party, had set aside their differences to remain united against Israel.

Sharon advisers suggested that any large military operation in Gaza would likely wait until after U.S. Secretary of State Condoleezza Rice's scheduled visit later this week. The prime minister has pledged that the withdrawal, known as disengagement, will not be carried out under Palestinian attacks. A large march against the disengagement plan is scheduled to begin Monday and move toward the Gaza Strip. An Israeli military official said it could draw troops away from the effort and delay any push into Gaza.

A female relative of Hamas commander Sayid Sayem grieves after Israeli forces killed him in the city of Khan Younis. Sayem, 31, was shot through the neck on the roof of his house.Emi Shakad, the security chief of the Gush Katif bloc of Jewish settlements in Gaza, evacuates a child after a house in Neve Dekalim, the largest Jewish settlement in Gaza, was hit by a homemade rocket. At least six people were injured in the attack.