GAZA Israeli tank fire killed four Palestinians in the Gaza Strip on Saturday after militants blew up an Israeli army jeep with an anti-tank missile, wounding four soldiers.
Palestinian fighters retaliated by firing rockets into southern Israel and an Israeli air strike targetted a rocket crew, killing a Palestinian militant, the Israeli army said.
The flareup carried the risk of further escalation. Explosions were audible and projectiles lit up the sky over Gaza shortly before midnight, but no further details were immediately available.
Palestinian militants vowed to take revenge for the deaths of the four civilians and the 25 wounded. Israel warned residents of communities near the Gaza border to stay within 15 seconds of their blast shelters in case of a rocket salvo.
Saturday's casualty toll was one of the highest in a single incident in Gaza in recent months.
Palestinians said a crowded mourning tent in the Shijaia neighbourhood was full of people paying respects to a bereaved family man when the tank shell exploded.
Ambulances, private vehicles and motorbikes rushed the wounded to hospital, eyewitnesses said. Among those killed was an 18-year-old youth.
"The occupation's targeting of civilians was a grave escalation that must not pass in silence," said Fawzi Barhoum of the Islamic movement Hamas which rules Gaza. "Resistance must be reinforced in order to block the aggression."
Israel denies targeting civilians.
The Israeli military said an anti-tank missile was fired at an army patrol along the security fence in the northern Gaza Strip. "Four soldiers were injured as a result," a statement said.
Just before midnight, the Israel Defence Forces (IDF) confirmed an air strike in the north of the narrow coastal enclave.
"A short while ago, the IDF targeted a rocket launching squad in the northern Gaza Strip moments after it fired rockets towards southern Israel. A direct hit was confirmed.
"Over the past few hours, 25 rockets fired from the Gaza Strip hit southern Israel," the IDF statement said.
Gaza's armed Islamic Jihad movement identified the dead man as a local commander named Mohammed Shkokani.
It was the second Israeli air strike of the day. In a separate incident at another location, four people were wounded by airforce fire in the town of Khan Younis.
Saturday's clashes come at a time of renewed tension along the Israel-Gaza frontier, only some two weeks after Egyptian mediation calmed an earlier flare-up.
In an attack on Thursday, a 12-year-old Gaza boy was killed by Israeli gunfire as troops fought a gun battle with Palestinian militants. Shortly afterwards, militants blew up a tunnel packed with explosives near the border.
The Gaza Strip, a coastal territory crowded with more than 1.5 million people, many of them refugees, is controlled by Hamas Islamists who reject Israel's right to exist. It is also the base for a number of other Islamic militant groups.
One of these, called the Popular Resistance Committees, said it had fired rockets at communities close to the border and the towns of Sderot and Netivot in southern Israel, in what it called "the revenge invoice" for the deaths in Gaza.
There was no report of casualties on the Israeli side.
In December 2008, Israel responded to repeated rocket attacks from Gaza by bombing the enclave for a week then invading with ground forces in a three-week war in which over 1,400 Palestinians were killed and 13 Israelis died.
Israel says it holds Hamas solely responsible for any violence emanating from the Gaza Strip, regardless of which group actually fires rockets or mortars.
(Writing by Ori Lewis and Douglas Hamilton. Editing by Douglas Hamilton)