Jerusalem ? Pressing what a security official called an all-out campaign against the militant group Hamas, Israeli forces Thursday carried out their third airborne attack in 24 hours in the Gaza Strip, killing seven Palestinians, including a Hamas fugitive, his wife and 3-year-old daughter in a helicopter missile strike.

The attack and the killing of an Israeli by Palestinian gunmen in a drive-by shooting in the West Bank were the latest deadly assaults in a surge of violence that has imperiled an American-backed “road map” to peace launched last week at a Middle East summit.

Prime Minister Ariel Sharon vowed Wednesday to pursue Palestinian militants “to the bitter end,” and Hamas on Thursday threatened a series of revenge attacks and cautioned foreigners to leave Israel, suggesting that the two sides were girding for a new phase of conflict after more than 32 months of bloodletting.

Bush administration officials said an American envoy, John Wolf, would be dispatched this weekend to Israel for urgent talks to save the road map, which calls for mutual steps to end violence and renew negotiations leading to a peace agreement and a Palestinian state.

In the latest Israeli assault Thursday, Israeli helicopters fired missiles at a car carrying Yasser Taha, a wanted fugitive from the military wing of Hamas.

Seven people were killed, including Taha, his wife and their 3-year old daughter, and 30 others were injured. Witnesses said the last missile landed after bystanders had rushed to the stricken car.