GAZA CITY, Gaza Strip (AP) — Israeli aircraft kept up a relentless string of attacks on Hamas-ruled Gaza today, smashing a government complex, security installations and the home of a top militant commander as thousands of Israeli ground troops, backed by tanks and artillery, massed along the border and waited for a signal to attack.

Israeli Prime Minister Ehud Olmert told President Shimon Peres today that the aerial phase of the operation is “the first of several” phases of attack that have been approved, an Olmert spokesman said.

Warplanes launched their bruising aerial offensive on Saturday after the Islamic Hamas defied Israel’s warnings that it would not stand for the rocket barrages on southern Israel that resumed nearly two months ago, toward the end of a recently expired truce.

More than 360 Palestinians have been killed, most of them members of Hamas security forces but at least 64 of them civilians, according to the United Nations. The toll includes two sisters, aged 4 and 11, who perished in an airstrike on a rocket squad in northern Gaza today.

Militants, battered but unbowed, have pressed on with their rocket and mortar assaults, killing three Israeli civilians.