The Israeli occupation force said it targeted two offices of the al-Aqsa Martyrs Brigades, an armed group from President Mahmoud Abbas's Fatah faction, and a bridge used to reach an area used to fire rockets at Israel. There were no casualties.

The attacks came after Israeli leaders vowed to enforce a no-go zone in the north of the strip, but the army said Tuesday's air strikes were a specific response to Palestinian rocket fire rather than aimed at enforcing the buffer zone.

The assaults were launched after Palestinian rockets hit farming communities in Israel. The army said it struck al-Aqsa buildings because the group was involved in the rocket firing.

The makeshift rockets fired by Gaza resistant fighters rarely cause casualties, but could complicate Prime Minister Ariel Sharon's campaign for re-election in a March ballot on the strength of a Gaza pullout he had said would boost Israel's security.

Haaretz newspaper said the Israeli occupation force would "take more aggressive action in northern Gaza," to carve out a zone to prevent rocket firing on Israel.

"NO-GO ZONE"

The Israeli occupation force has been given the go-ahead to enforce the zone near the Gaza border with Israel and has urged Palestinian police to evacuate positions, a request rejected by the Palestinians.

Israel's threat to enforce the zone has recalled the "Security Zone" it established in southern Lebanon to prevent rocket fire by resistant fighters. Unlike in Lebanon, Israel says it will not use ground troops, only airstrikes and shelling.

Rocket fire has continued despite Israel's withdrawal from Gaza after 38 years of occupation. Gunmen call it a response to Israeli strikes and the violence has soured hopes the pullout would lead to a quick resumption of peacemaking.

Defiant resistant fighters said they would step up the barrages if Israel attempted to curb rocket fire with airstrikes.

"Any attack on our people on any part of Palestine will be met by a decisive and violent reaction that will not be limited to a time or place," a statement issued by the al-Aqsa brigades, Islamic Jihad and the Popular Resistance Committees said.

Sharon has ruled out any talks on statehood in the West Bank and Gaza until Palestinians disarm resistant fighters, a process that is meant to start under a U.S.-backed peace plan.

The stakes are high for Sharon ahead of the March 28 election, for which the ex-general is standing on a platform of ending conflict with the Palestinians after quitting his rightist Likud to move toward the political center.

Opinion polls show Sharon would win re-election, but more violence could strengthen his main rightist challenger, Benjamin Netanyahu, who denounced the Gaza pullout as a surrender to Palestinian militants that would only encourage attacks.