MISRATA (AFP) - Libya's interim government was poised on Saturday to launch a final assault on towns still loyal to Moamer Gaddafi after a deadline for surrender expired, with its leader saying it was now in his military commanders' hands to decide when to act. Libya's new interim leader Mustafa Abdel Jalil arrived in Tripoli for the first time since his forces seized the city last month and was treated to a red-carpet welcome at the Metiga military base, an AFP correspondent reported. His arrival in Tripoli, where he was mobbed by hundreds and had to be protected by a thick human chain, was eagerly awaited in hopes it would help tackle rivalries emerging among rebel groups that overthrew Gaddafi. The battle for one Gaddafi stronghold, Bani Walid, already got off to a fitful and unscheduled start overnight, but fighters of the National Transitional Council withdrew on Saturday, apparently in anticipation of a NATO air strike. "Last night the deadline passed," Abdel Jalil told local leaders in the long-besieged town of Misrata, as he made his way to Tripoli. "We have extended it more than once, trying to clear the way for a peaceful resolution." "Now the situation is in the hands of our revolutionary fighters," he said, effectively giving commanders authority to attack Bani Walid, Sirte, Sabha and other pro-Gaddafi enclaves. "We have spoken to them through their leaders and have left it to them to make the decision whenever they chose," he said. That was echoed in Tripoli by Omar al-Hariri, who oversees NTC military affairs and who told AFP that the war against pro-Gaddafi pockets in Bani Walid and Sirte could take up to a week to win depending on the intensity of the resistance. After clashes broke out overnight between NTC "sleeper cells" and pro-Gaddafi forces inside and near Bani Walid overnight, NTC fighters launched a widespread assault on Saturday. "We launched this morning the widespread assault we had spoken about in order to enter and capture Bani Walid after receiving reinforcements from other areas," said the NTC's Abdullah Kenshil, who has been unsuccessfully negotiating the surrender of the town. "The rebels now control positions in the north of the town and are combing through the area where snipers are positioned on rooftops," he said, adding that one of the fighters was shot and killed by a sniper. Kenshil said NTC fighters "later withdrew for tactical reasons that could be linked to military operations that NATO might be planning." A number of former regime officials, including Gaddafi spokesman Mussa Ibrahim, are believed to be holed up in Bani Walid, while the whereabouts of Gaddafi is unknown. Meanwhile, fighters of the new regime on Saturday moved five kilometres from west of the town of Red Valley towards Sirte, an AFP reporter said.