Apache helicopter gunships fired missiles at Fatah offices in Gaza City, as well as Palestinian security offices in other suburbs.
“Israeli aircraft simultaneously attacked various targets in the Gaza Strip,” said an Israeli army spokeswoman, speaking to AFP.
“Following the Palestinians firing another Qassam rocket at our territory, our aircraft attacked a building used for terrorist purposes by Fatah in Gaza City, another used by the Popular Resistance Committees at Tel Hawa southwest of Gaza City, and finally a building sheltering PFLP terrorists responsible for many anti-Israel attacks in Bureij camp.”
A bridge in northern Gaza’s Beit Hanoun was destroyed, and an Israeli military source said a leading traffic artery for militants had been wrecked.
A missile was also fired at the Bureji refugee camp in central Gaza.
The escalating violence has shattered hopes that Israel’s troop pullout from Gaza two weeks ago would boost chances for peace.
The pre-dawn raids plunged much of Gaza City into darkness, cutting electricity to many of its 350,000 residents for two hours.
Rescue workers sifted through the rubble in Gaza and El Bureij refugee camp.
There have been no reported casualties.
Hours earlier Israeli artillery gunners opened fire on suspected rocket launching sites in northern Gaza after dark on Tuesday, shelling the area for the first time since Israel’s September 12 exit from the zone its army had ruled for 38 years.
The shelling came after a rocket slammed into a street in the southern Israeli town of Sderot.
However militant group Islamic Jihad afterwards joined Hamas is saying it would observe a truce if Israel halted the strikes.
Israeli troops also mounted fresh raids in the occupied West Bank, where it has arrested dozens of suspected militants in recent days.
The West Bank raids followed Tuesday’s release of a videotape and statement by Hamas claiming responsibility for the slaying of an Israeli man.
The upsurge in violence could undermine Israeli Prime Minister Ariel Sharon’s pledge that the Gaza pullout would boost security for the Jewish state.
It also underlines the factional chaos in Gaza confronting Palestinian President Mahmoud Abbas as he seeks to make Gaza a peaceful proving ground for a state that Palestinians aspire to build in both Gaza and the occupied West Bank.