Pat Dollard | Young Americans

GAZA CITY, Gaza Strip (AP) - Israeli air strikes killed two Hamas militants in Gaza early Saturday, a day after Israel sealed the territory and bombed an empty Hamas government ministry in an intensifying campaign to halt rocket fire on Israeli border towns.

In New York, U.N. Secretary-General Ban Ki-moon implored Israel to reverse its unprecedented decision to close the border crossings completely, warning that the cutoff of supplies is provoking a humanitarian crisis among 1.4 million Gazans. For the past seven months, since the violent Hamas takeover of Gaza in June, Israel had severely restricted access to Gaza, but basic food supplies and fuel were still getting through.

The Gaza blockade and the bombing of the government ministry are part of an Israeli attempt to halt a surge of rocket fire on Israeli border towns. On Friday, 16 rockets hit southern Israel, including one that damaged a daycare center. Children were inside the building at the time, but no one was hurt.

Thirty-six Gazans have been killed in Israeli attacks since Tuesday, including at least 10 civilians.

Moderate Palestinian President Mahmoud Abbas on Friday denounced the Israeli air strikes as “brutal,” but also accused Hamas of trying to destroy the Palestinians’ national aspirations. Abbas, who controls the West Bank, reiterated his demand that rival Hamas relinquish power in Gaza. However, the air strikes and the blockade appeared to be increasing support for Hamas among Gazans.

Hamas was defiant Saturday, saying it would keep firing rockets at Israel. “We will not surrender and we will not raise white flags,” said Hamas spokesman Ayman Taha.

Friday’s attack on the Palestinian Interior Ministry appeared to signal a new phase in the cross-border violence between Israel and Gaza.

An Israeli warplane bombed the empty building, flattening one wing, killing a woman at a wedding party next door and wounding at least 46 civilians, some of them children playing soccer in the street. The blast blew out windows in neighboring high-rises, left hundreds without electricity and water and terrified residents.

Five of the wounded remained in critical condition Saturday.

The attack was the first on a ministry building since the Hamas takeover, and was seen as a message to Hamas that Israel was ready to step up air strikes if rocket attacks continue. The building had been empty since it was severely damaged in a July 2006 airstrike, but was seen as a symbol of Hamas authority.

Early Saturday, Israeli forces backed by several tanks and bulldozers entered Gaza and searched homes in the town of Jebaliya. Hamas gunmen exchanged fire with the troops, and Israeli aircraft fired three missiles, killing two Hamas fighters involved in the fighting, hospital officials said.

An escalation of the Gaza fighting could complicate President Bush’s efforts to prod the sides toward a final peace deal by year’s end and sour talks between Israel and the Abbas government.