Nato's secretary general has urged the international community to prepare for a post-Gaddafi Libya, as the alliance steps up its campaign. "The time to start planning is now," Anders Fogh Rasmussen told reporters following a meeting of Nato defence ministers in Brussels. He said the alliance's nine-week air campaign had been highly successful in saving civilian lives. However, Col Muammar Gaddafi has vowed to remain in Libya "dead or alive". He urged supporters to defy Nato and gather at his compound in the capital, Tripoli. Earlier, more explosions were heard in Tripoli after a day of intensified bombardment on Tuesday. Alliance ministers met at Nato headquarters to discuss the Libyan campaign on Wednesday. Afterwards, Mr Rasmussen told reporters that "real progress" had been made. Nato action, he said, had "prevented a massacre" in Benghazi in the east - the rebels' stronghold - and in the rebel-held city of Misrata in the west. Defiant Gaddafi Nato ministers, Mr Rasmussen said, had "agreed to keep up the pressure for as long as it takes". He added that Col Gaddafi would eventually be forced out. "When he goes the international community must be ready," he said. He said the UN and other bodies should work to "ensure a smooth transition" to democracy. Last week Nato extended its air operations over Libya for another 90 days, as it increased the scope of its UN-mandated campaign to protect civilians. Since then, British and French attack helicopters have gone into action and command centres in Tripoli have been pounded. On Tuesday Nato carried out its heaviest daytime raids of its campaign on what it said were command and control centres in and around the capital, with more than 20 air strikes by low-flying jets. Libyan television reported Col Gaddafi's Bab al-Aziziya compound had been hit. The whereabouts of the Libyan leader remain unknown. Col Gaddafi and his sons reportedly spend each night in different locations to evade the Nato air strikes. In a defiant audio address on state TV on Tuesday, he said the Libyan people would soon defeat their enemies. "The Libyan people will march, in the direction of the east or the west, or to any place where there are armed gangs to strip them of their arms without fighting," Col Gaddafi said. Addressing Nato, he added: "Your planes will not be able to stop these marches of the millions, nor will the armed gangs that you support be able to resist for even a minute in the face of these marches." Source: BBC