Palestinian resistance fighters in Gaza responded to the killing of one of their members by Israeli forces in the Occupied West Bank by firing rockets into Israel on Tuesday.

The retaliation by Gaza-based fighters was met with an Israeli air strike on the impoverished territory later in the day.

Islamic Jihad said its armed wing had fired four rockets in response to the overnight killing of one of its members by Israeli security forces. Palestinian witnesses say Jihad Nawhda, 20, was shot by undercover security forces near the Occupied West Bank town of Jenin. The Israeli military claims to have opened fire on Nawhda after he attempted to escape.

Two Islamic Jihad fighters were wounded in the Israeli air raid, which targeted a rocket launcher in the northern Gaza Strip, Palestinian medics said.

Earlier, the three rockets had struck open areas in southern Israel where they caused no casualties or damage.

Islamic Jihad, which is far smaller than Hamas but regularly retaliates against attacks by Israel, urged all Palestinian factions to reject any extension of an Egyptian-mediated truce that had brought calm to the areas in and around the Gaza Strip.

"The truce with the enemy has not enabled the realization of our goals and represents a threat against the interests of our people," a statement said.

Israel first began its blockade of Gaza, where roughly half of the 1.5 million population is dependent on international humanitarian aid, after Hamas won legislative elections in 2006. Following the ouster of Fatah by Hamas in what many have described as a pre-empting of an impending US- and Israeli- backed offensive aimed at pushing the Islamists from the territory, Israel further tightened its grip.

UN and EU officials, along with scores of human rights organizations, have blasted the siege as "collective punishment of a civilian population," an act that the Fourth Geneva Convention defines as a war crime.

Last week, a top UN human rights official termed Israeli policies against Palestinians a "crime against humanity."

Under the terms of the six-month Egyptian-brokered cease-fire that went into effect in June, Israel was to lift its blockade if Hamas reigned in fighters launching homemade rockets into the Jewish state. But while the Islamists virtually halted attacks from Gaza, Israel never honored its pledge.

The truce remained intact until November 4, when Israel invaded Gaza with tanks and soldiers in an offensive that killed seven Hamas members. Palestinian fighters retaliated for the invasion by resuming rocket fire into Israel.

Hamas' Syria-based political chief, Khaled Meshaal, has said his movement would not renew the agreement, but Hamas leaders in Gaza were less categorical.

Israel, despite shattering the agreement early last month, has said it wants the truce to continue as long as militants in Gaza halt their retaliatory attacks.

"We do not fear an operation in Gaza but we are in no rush," Defense Minister Ehud Barak was quoted as saying on Tuesday. "Calm will be answered by calm, but if the conditions force us to respond, we will respond at the time and place we deem right."

Palestinian President Mahmoud Abbas expressed hope the truce would be extended. "We urge all parties to maintain it as its end would worsen the suffering of our people," he said.

Several Israeli ministers have called for a tougher line against Gaza retaliations, and Foreign Minister Tzipi Livni, who hopes to become premier after February 10 elections, has said Israel "cannot allow Gaza to remain in the hands of Hamas."

More than 200 rocket attacks have been carried out in a flare-up of violence since November 4. Israel has killed 17 Gaza militants and several civilians over the same period.

As it has repeatedly in recent weeks, Israel responded to the latest attacks by sealing off the impoverished territory and halting the delivery of humanitarian supplies sent by aid agencies.

On Monday, the so-called Middle East diplomatic Quartet condemned "indiscriminate attacks on Israel" and expressed its "acute concern" over the humanitarian impact of the siege.

The international mediation group made up of the European Union, Russia, the United Nations and the United States also called for the truce to be extended and respected.

In a statement issued after a meeting in New York, the Quartet urged Israel to allow continuous delivery of humanitarian supplies into the coastal strip.

Also on Tuesday, a court martial in the Gaza Strip sentenced a Palestinian man to hang for "treason, espionage and collaborating" with Israel, its chief magistrate said. Mohammad Ali Hassan Saidam, 34, confessed after his arrest in February to having supplied intelligence to Israel that led to the assassination of Palestinian resistance fighters, Ahmad Atta said.