GAZA CITY (AFP) - Israeli forces killed one Palestinian and wounded three others in an air raid on the Gaza Strip on Saturday, a day after the end of a shaky six-month truce, medical sources and witnesses said. The attack amid UN and US calls for calm took place near the northern town of Jabalya when a warplane fired three missiles at the Palestinians, witnesses said. Ali Hijazi, 24, one of the Palestinian Authority's security services, was killed. Of the three wounded, two are in a critical condition, Muawiya Hassanein, head of the Palestinian health ministry's emergency services, said. Three of the men belonged to the Al-Aqsa Martyrs Brigades, an offshoot of moderate Palestinian President Mahmud Abbas's Fatah faction, witnesses said, adding that a civilian was also hurt. Al-Aqsa identified Hijazi as its local commander and said the dead man, who was to have been married on Sunday, was allegedly responsible for handling rocket attacks on Israel. "We won't delay our response to this assassination. All options are open and the reaction will come from all Palestinian groups," Abu Thaer, the brigades' spokesman, told AFP. Among the thousand or so Palestinians following the funeral procession on Saturday, many demanded "vengeance," calling for "suicide attacks." Hijazi's fiancTe Sabrin, crying in her house in the Jabalya refugee camp, told AFP: "I hope God will avenge him." An Israeli army spokesman said the airstrike was launched after two rockets were fired into southern Israel without causing any casualties. The Islamic Jihad movement claimed responsibility for firing one of the rockets, while the Ezzedine al-Qassam Brigades, the military wing of Hamas, the rulers of the besieged Palestinian enclave, said it fired six mortar rounds at Israel. "It is the first time we have fired on Israel since the end of the truce," it said in a statement. "We issue a warning to the Zionist enemy: all attacks against the Gaza Strip or any new crime will trigger a large-scale confrontation and we will retaliate very fiercely," Ezzedine al-Qassam had said on Friday. An Israeli army spokesman told AFP that four mortar rounds fell on Israel near a crossing point in southeast Gaza without causing injury or damage. Tensions have been surging in and around Gaza after Hamas said it would not extend the June 19 truce with Israel and warned it would respond to any attack. Hamas, which has controlled the territory of 1.5 million people since seizing power 18 months ago, and Israel have both said they would respond if attacked, but neither has said it would go on the offensive at this stage. Israeli Defence Minister Ehud Barak told the Haaretz newspaper "if the quiet continues, there will be quiet. If the lull is shattered, we will act." Late on Friday, UN Secretary General Ban Ki-moon said he was "extremely concerned" about the escalation of violence in the Gaza Strip and urged an extension of the truce. "The Secretary-General is extremely concerned at statements calling into question the continuation of the Egyptian-brokered calm in and around Gaza," a statement from his office said. US Secretary of State Condoleezza Rice warned that renewed violence against Israel would only hurt the Palestinians. "Overall, Hamas needs to concentrate on turning away from violence," she told reporters when asked if a new outbreak of violence would complicate the Israeli-Palestinian peace talks Rice helped launch a year ago. "A renewed threat of violence against Israel is going to do nothing for the people of Gaza except deepen their misery which has been imposed by Hamas as it is," she said. Israel responded to violence that erupted in early November by tightening sanctions and closing its crossing points with Gaza, halting deliveries of humanitarian aid and other basic supplies. Abbas, whose mandate as Palestinian president has extended only to the West Bank since Hamas seized Gaza, met in Washington on Friday for farewell talks with US President George W Bush. He was heading on to Moscow on Saturday for a three-day visit.