The blast went off late on Friday evening
A suicide bombing has killed "several" people and injured at least 20 outside a night club in the Israeli coastal city of Tel Aviv, police report.
The bomber set off a device as people queued to get into the club, which is in a popular seafront area, a police spokesman told Reuters news agency.
Two Palestinian militants groups have each claimed responsibility.
Such groups had been observing an unofficial truce with Israel for some three weeks.
"We passed the crosswalk and suddenly there was a huge explosion," an unnamed witness told Israel's Army Radio.
"The whole area of the club was destroyed. Debris fell to the ground and cars were smashed."
Militant attacks fell away in the days after Israel and the Palestinian Authority reached a truce at a summit in Egypt on 8 February.
The Islamic Jihad group said it had carried out the attack, in a statement carried by Reuters news agency.
"This is a martyrdom operation that shows we are not committed to the ceasefire because Israel is continuing to kill and arrest Palestinians," it said.
But AFP news agency received another claim from the al-Aqsa Martyrs' Brigades group. "
Here we go again...
