One Palestinian was killed and more than 20 others wounded in a failed Israeli helicopter strike on two Palestinian activists in the northern Gaza Strip, security sources said. Palestinian sources said two attack helicopters fired a volley of rockets just outside the town of Jabaliya, targeting two members of the group Hamas but killing instead a 60-year-old passerby. An AFP correspondent at the scene said one car was completely destroyed but quoted witnesses as saying the three or four Palestinians escaped. Several other cars were also damaged. Medical sources said many of the more than 20 wounded were women or children. One of men injured had been driving a cart pulled by a donkey who was killed in the strike, they said. The Islamic group Hamas identified the targets as Wahel Ikalan and Khaled Massoud, both members of its armed wing, who escaped. An advisor to Palestinian leader Yasser Arafat, Nabil Abu Rudeina, said the Israeli attacks had "taken the situation back to zero" and that the Palestinian leadership could now ask for an emergency debate at the UN Security Council on "the escalation". The Israeli army refused immediate comment on the raid. The raid came two days after four Hamas members were killed by rocketfire. A top Hamas leader, Ismail Abu Shanab, was slain with two bodyguards on Thursday in the first of a series of attacks that has the Palestinians vowing vengeance. Israel swore to press its campaign of "targeted killings" after bomb attack killed 21 passengers on a Jerusalem bus last week. **PHOTO CAPTION*** Angry Palestinians shout anti-Israel slogans as they gather around a car hit in an Israeli helicopter attack outside the northern Gaza Strip town of Jabalia. (AFP/Mohammed Abed)