The Israeli airstrikes knocked out power in Gaza City, plunging virtually all of the city into darkness. The army said it targeted three buildings used for "terror activity" by the ruling Fatah Party, as well as two smaller armed groups, the Popular Front for the Liberation of Palestine and the Popular Resistance Committees.
Palestinian security officials said the buildings suffered substantial damage, but there were no injuries.
The airstrikes came hours after Islamic Jihad militants on Tuesday declared a halt to their recent rocket attacks, and armed Palestinian groups pledged to honor a tattered cease-fire, seeking to end the Israeli offensive.
Tensions were further inflamed when Hamas militants released a video showing a bound and blindfolded Israeli businessman whom they kidnapped and later killed. The kidnapping appeared to signal a new tactic in the militants' fight against Israel.
Israel launched its offensive last weekend in response to rocket fire from Gaza. It has carried out numerous airstrikes in Gaza and arrested hundreds of Palestinians in the West Bank, saying the operation will continue until the rocket attacks stop.
Israel says the strong reaction is necessary to show that new rules are in place following its recent withdrawal from Gaza, after a 38-year occupation, and that attacks from the area won't be tolerated.
Islamic militant and political groups met late Tuesday to discuss the Israeli attacks. After the talks, the leader of Islamic Jihad, Mohammed al-Hindi, said his group cease the rocket attacks. The larger Hamas militant group declared an end to rocket attacks earlier this week.