( dpa )- Responding to a barrage of rocket and mortar fire, Israeli airstrikes killed five Palestinians in Gaza Wednesday - including a boy, his father and uncle who died when a missile missed its target and hit their civilian car.
Israeli troops in the West Bank also killed a senior commander of the radical Islamic Jihad, who had been sought by Israel for years.
Palestinian militants launched 47 rockets and mortars at Israel after midnight to avenge bloody Israeli-Palestinian fighting in Gaza Tuesday which left 19 Gazans dead, including the son of powerful Hamas leader Mahmoud al- Zahar .
Israeli police declared an emergency in the town of Sderot , just north-east of Gaza, and other communities neighbouring Gaza, which bore the bulk of the rockets. Several missiles struck the southern Israeli port city of Ashqelon .
Television footage on Israel's evening news showed schoolchildren cowering and praying under their classroom tables as the rockets struck Sderot .
Hamas ' armed wing, which has limited itself for the past year to mortar attacks on Israeli military bases bordering Gaza, took responsibility Wednesday morning for launching as many as 60 of its own Qassam rockets at the civilian population centres , in addition to 75 mortars and three rocket-propelled grenades.
Israel's Army Chief of Staff Gaby Ashkenazi told a news conference in Jerusalem there was no "perfect answer" to the rocket fire, but warned Israel would "broaden" its military actions in Gaza if it had to.
The Israeli airstrike in eastern Gaza City Wednesday morning missed its target, hitting a civilian car driving close to another transporting militants .
Three members of the same family, 27-year-old Mohammed al- Yazji , his eight-year-old son Ameer and the boy's 40-year-old uncle were killed and five others injured, the director of Gaza's ambulance service, Muawiya Hassanain , reported.
An Israeli army spokeswoman, Major Avital Leibovich , expressed "regret" and said the strike on the wrong vehicle was "under operational investigation."
A second airstrike later Wednesday evening near the central Gaza Strip refugee camp of al- Bureij killed two militants of the Popular Resistance Committees (PRC) and injured three others, one of them seriously, hospital officials said.
An Israeli army spokeswoman said the target was a car loaded with weapons and PRC militants, involved in the production and transportation of rockets used against Israel.
The escalation in violence in and around Gaza comes days after US President George W Bush visited Israel and the Palestinian areas, as a result of which the parties began long-delayed peace negotiations Monday on the "core issues" of their mutual conflict.
Also Wednesday, Israeli police cleared two unauthorized settler outposts in the northern West Bank.
The handful of activists at one of the outposts, Harchivi , near Nablus , fled when police arrived, spokesman Micky Rosenfeld said.
Most of the 20 settlers at the second outpost, Shvut Ami, also in the Nablus area, also left without having to be forcibly evacuated, although some struggled and had to be carried away.
It marked the first time outposts have been cleared since the Annapolis conference on November 27, at which Israeli Prime Minister Ehud Olmert and Palestinian President Mahmoud Abbas renewed the peace process.
During his visit last week, Bush had said "the agreement was to get rid of outposts, illegal outposts, and they ought to go."
Thousands of Hamas supporters meanwhile lined up at a mourners tent in Gaza Wednesday to pay their sympathy to al- Zahar , who also lost another son in a September 2003 Israeli airstrike .
Israeli officials had expressed fear the killing of Hussam al- Zahar could damage efforts to finalize a prisoner exchange deal that would include the release of an Israeli soldier held captive in Gaza since June 2006.
But al- Zahar , in a rare interview with Israel's Channel 10 television which it said was a break from a years-long boycott of Israeli media, said he had "no information" on a prisoner-exchange deal.
Troops in the West Bank, meanwhile, shot dead senior Islamic Jihad commander Walid Obeidi during an early-morning arrest raid in a village south of of Jenin . An Israeli military spokesman said he tried to resist arrest and opened fire at the troops.