BEIRUT (Reuters) - Hizbollah said on Saturday it would abide by any U.N.-backed ceasefire in Lebanon, but would resist Israeli troops expanding their offensive in the south. Sayyed Hassan Nasrallah, leader of the Shi'ite Muslim guerrillas, said Hizbollah would cooperate with Lebanese and U.N. troops due to be deployed in south Lebanon under a Security Council resolution adopted on Friday to end the month-old war. "Once there is an agreement to stop the hostilities or the military operations, the resistance will abide by it," Nasrallah said in a speech broadcast on Hizbollah's al-Manar television. But he said Hizbollah had the right to resist any Israeli soldiers who remained on Lebanese soil. Despite the U.N. resolution's demand for a "full cessation of hostilities," the Israeli army pushed deeper into Lebanon and air strikes killed up to 20 people on Saturday. Helicopters lifted hundreds of Israeli troops into the south as part of an expanding offensive launched even though Prime Minister Ehud Olmert has backed the U.N. vote. Olmert was expected to ask his cabinet to approve the resolution on Sunday. Lebanese Prime Minister Fouad Siniora said the final resolution was a victory for Lebanese diplomacy. "The resolution is a triumph for the Lebanese negotiators, compared to the previous draft," he told reporters before an emergency cabinet session to discuss the U.N. measure. President Bush welcomed the resolution, saying Hizbollah and its sponsors Iran and Syria had brought an "unwanted" war to the region. Israel's top general said the offensive would go on until it was clear how any U.N.-backed ceasefire would take effect. "We will continue to operate until we achieve our aims," Lieutenant-General Dan Halutz told reporters. Hizbollah fired at least 30 rockets into Israel and medics said three people were lightly wounded. A U.N. envoy said earlier the United Nations expected the Israeli assault to wind down in one to two days and an expanded international force to begin deploying in a week to 10 days. "We are not starting from zero," Alvaro de Soto, the U.N. special envoy for the Middle East peace process, said, adding that several countries had offered contingents for the force. The U.N. resolution authorizes up to 15,000 U.N. troops to move into Lebanon to enforce a ceasefire. France is widely expected to lead the force, which will expand the existing U.N. Interim Force in Lebanon (UNIFIL), but have a stronger mandate. UN PEACEKEEPER WOUNDED Bush said the U.N. resolution aimed to "stop Hizbollah from acting as a state within a state, and put an end to Iran and Syria's efforts to hold the Lebanese people hostage to their own extremist agenda." French Foreign Minister Philippe Douste-Blazy made clear in an interview with Le Monde newspaper that the mission of the larger UNIFIL would not include disarming Hizbollah by force. "We never thought a purely military solution could resolve the problem of Hizbollah," he said. "We are agreed on the goal, the disarmament, but for us the means are purely political." UNIFIL said a Ghanaian peacekeeper had been wounded by Israeli artillery fire near the southern village of Haris. Relief officials said Israel was still denying permission for aid convoys to reach distressed civilians in south Lebanon. Israeli troops pushed west toward Ghandouriyeh, a village 11 km (7 miles) inside Lebanon, their furthest penetration yet, security sources said. Hizbollah said it had destroyed 16 tanks in the fighting and inflicted heavy Israeli casualties. The Israeli army said more than 30 soldiers had been wounded. It said it had killed more than 40 Hizbollah fighters in the last 24 hours and destroyed several rocket launchers. Air strikes in the south killed up to 15 people in the village of Rshaf and four civilians in Kharayeb, security sources said. Raids in the Bekaa Valley killed one civilian. The U.N. resolution said Hizbollah must halt all attacks and Israel must stop "all offensive military operations." At least 1,061 people in Lebanon and 124 Israelis have been killed in the war that began after Hizbollah guerrillas captured two Israeli soldiers in a cross-border raid on July 12. The planned U.N. force will monitor the withdrawal of Israeli troops and help the Lebanese army maintain a ceasefire. The resolution stipulates that after fighting stops, Israel must withdraw all its forces from Lebanon at the earliest opportunity, in tandem with a U.N.-Lebanese troop deployment. It also calls for a zone between the Litani river and the Israeli border "free of any armed personnel, assets and weapons" other than those of the U.N.-Lebanese forces, implying a Hizbollah withdrawal or disarmament.