Four Palestinians, including a top member of Islamic Jihad, have been killed in an Israeli air strike in Gaza.
Three members of the same family were among the dead, including a child.
The attack prompted Islamic Jihad to pledge continued rocket attacks on Israel.
The militant killed, Mohammad al-Dahdouh, was a senior Islamic Jihad commander responsible for recent firings of advanced Russian-made rockets into Israel.
The air strike occurred hours after Palestinian General Intelligence chief Tareq Abu Rajab was wounded in an attempted assassination attempt.
Mr Rajab, a security official loyal to President Mahmoud Abbas, was among six security officials wounded in an explosion in an elevator at his headquarters in the Gaza Strip.
One of his bodyguards died in the blast
The incident followed a night of clashes between gunmen from the rival Hamas and Fatah factions.
Presidential spokesman, Nabil Abu Rudeina, condemned the blast and called for an immediate inquiry into the bombing.
Abu Rajab, who was appointed by Mr Abbas in April 2005, was previously targeted in August 2004 when gunmen seriously wounded him in a shooting in Gaza City.
Palestinian security officials said that Hamas militants from the new security force might have been responsible for the explosion.
Dozens of Fatah gunmen surrounded the Palestinian parliament in the West Bank city of Ramallah after the blast and issued a statement urging Mr Abbas to dissolve the Hamas-led government and call new elections.
The US Secretary of State, Condoleeza Rice, has described the emergence of rival Palestinian security forces as very dangerous.
Dr Rice said she could not think of any stable democracy where competing forces were allowed to operate.
