Four Palestinians have been killed and at least 30 wounded in a series of Israeli air strikes in Gaza.
The attacks targeted Hamas' headquarters in Gaza City and a house which the Israeli military said belonged to a Hamas member.
Hamas' armed wing has threatened to renew suicide bombings in Israel after the incident.
This morning, Israeli Prime Minister Ehud Olmert had promised a 'severe response' to recent rocket attacks by Gaza militants on Israel.
Hamas has been launching rockets against Israel since the start of the latest bout of Palestinian infighting on Sunday, with 29 landing inside the Jewish state. Five Israelis have been wounded.
The air strike comes amid a tentative truce in Gaza following four days of factional violence that has left more than 44 Palestinians dead.
Palestinian President and Fatah leader, Mahmoud Abbas, was due to meet with Prime Minister Ismail Haniyeh of Hamas later today in an effort to make peace between their rival groups.
The unrest has cast doubts on the future of the fragile unity government involving President Abbas and Mr Haniyeh.
Tension between their parties has remained high since Hamas defeated the long-dominant Fatah in 2006 elections. The Islamist's win prompted international sanctions which plunged the impoverished territory further into crisis.
Despite the latest ceasefire, the fourth in as many days, five people died in sporadic violence overnight and gunmen opened fire on the home of Prime Minister Haniyeh.
At least 25 people were killed in clashes in Gaza yesterday.
