LONDON, England --A sweeping array of world powers called forcefully Tuesday for Moammar Gadhafi to step down as Libya's ruler. Some even hinted at secret talks on Gadhafi's exit. U.S. Secretary of State Hillary Rodham Clinton and British Foreign Secretary William Hague led the crisis talks in London between 40 countries and institutions, all seeking an endgame aimed at halting the Libyan leader's bloody onslaught against Libya's people. Although the NATO-led airstrikes on Gadhafi's forces aren't aimed at toppling him, dozens of nations agreed in the talks that Libya's future does not include the dictator at the helm. "Gadhafi has lost the legitimacy to lead, so we believe he must go. We're working with the international community to try to achieve that outcome," Clinton told reporters. As she spoke, U.S. officials announced that American ships and submarines in the Mediterranean had unleashed a barrage of cruise missiles at Libyan missile storage facilities in the Tripoli area late Monday and early Tuesday -- the heaviest attack in days. German Foreign Minister Guido Westerwelle echoed Clinton's words. "One thing is quite clear and has to be made very clear to Gadhafi: His time is over. He must go," Westerwelle said. "We must destroy his illusion that there is a way back to business as usual if he manages to cling to power." Both Clinton and the representatives of Libya's opposition -- who held a raft of talks on the margins of the London summit -- acknowledged there were few signs that Gadhafi is heeding those demands. There was no immediate comment from Russia, which abstained in the U.N. vote authorizing the airstrikes that began March 19. "He will have to make a decision," Clinton said. "And that decision, so far as we're aware, has not yet been made." Diplomats rejected suggestions that Gadhafi could be granted immunity but said work was under way to find a possible sanctuary for him. Italian Foreign Minister Franco Frattini said negotiations on securing Gadhafi's exit were being conducted with "absolute discretion" and that there were options on the table that hadn't yet been formalized. "What is indispensable is that there be countries that are willing to welcome Gadhafi and his family, obviously to end this situation which otherwise could go on for some time," he said. But the Italian diplomat insisted there was no option of immunity for Gadhafi. "We cannot promise him a 'safe-conduct' pass," he stressed. Libyan Foreign Minister Moussa Kusa visited Tunisia briefly, but there was no word if this was linked to the secret talks. French Foreign Minister Alain Juppe insisted it was up to the Libyan people to decide the dictator's fate. "They have to organize the future of their country and to decide what Gadhafi will become," he said. Hague said Tuesday's meeting brought clarity between allies and offered a key opportunity to discuss Libya's post-Gadhafi future with Libya's opposition Interim National Council, whose envoy, Mahmoud Jibril, held meetings with Hague, Clinton, British Prime Minister David Cameron and several European foreign ministers. Guma El-Gamaty, a Libyan opposition official, told reporters in London that Gadhafi must be held accountable for his brutalizing of civilians. "These crimes must not go unpunished. They should be punished at a fair trial held in a fair court," El-Gamaty said. U.N. special envoy Abdelilah al-Khatib, a former Jordanian foreign minister, will be returning to Libya to hold talks with both Gadhafi's regime and opposition figures. And the U.S. and France are both sending diplomats to the rebel-held Libyan city of Benghazi to bolster ties with opposition leaders. Those at the summit agreed to form an international contact group of at least a dozen nations and institutions aimed at coordinating political action and liaising with Libya's opposition. Sweden, while not a member of NATO, said it would send eight fighter jets to help enforce the U.N.-authorized no-fly zone over Libya. Turkey said it also will likely join the group. Still, the summit left a number of important questions open: Nations didn't discuss whether or not they should -- or legally can -- supply weapons to Libya's rebel fighters. There was also no open discussion of how to lure Gadhafi into exile and Qatar gave few details on its offer to help rebels sell crude oil on the international market. British diplomats also acknowledged there was no decision about the makeup of the contact group, though its first meeting is expected in Qatar in two weeks. In Washington, Adm. James Stavridis, the NATO Supreme Allied Commander in Europe, told Congress that officials have seen "flickers" of possible al-Qaida and Hezbollah involvement among the rebel forces. Some officials attending the London meeting acknowledged they had little knowledge of the opposition figures, including some on the 33-member interim council. However, Spanish Foreign Minister Trinidad Jimenez discounted the concerns, saying there was little evidence of al-Qaida involvement in the Libyan opposition. "When the first demonstrations and revolutions started in Tunisia and Egypt there was also speculation about who would join the street demonstrations," Jimenez said. "The reality was that the vast majority were demanding more democracy, more freedom and more rights. That is the impression we also have in Libya." Despite those worries, Clinton and Juppe both hinted that the international community may need to consider offering weapons to the rebels. "It is our interpretation that (UN Security Council resolution) 1973 amended or overrode the absolute prohibition on arms to anyone in Libya, so that there could be a legitimate transfer of arms if a country should choose to do that," Clinton said. Jimenez disagreed, saying the arms embargo applies to all those involved in fighting and suggested that any decision to arm the rebels would require a new U.N. resolution. Mahmoud Shammam, a spokesman for the Libyan opposition, told reporters in London that, properly equipped, rebels "would finish Gadhafi in a few days." "We do not have arms. We ask for the political support more than we are asking for the arms, but if we get both that would be great," Shammam said. Qatari Prime Minister Sheikh Hamad Bin Jabr al-Thani said the issue could be addressed later if the aerial campaign falls short of its goal of protecting Libyan civilians. "We have to evaluate the airstrike after a while to see if it's effective," he said. "We are not inviting any military ground (troops) ... But we have to evaluate the situation because we cannot let the people suffer for so long. We have to find a way to stop this bloodshed." Opening the talks, Cameron told diplomats that Gadhafi was pounding Misrata, the main rebel holdout in the west, with attacks from land and sea, and unleashing snipers to shoot people in the streets. The Libyan leader "has cut off food, water and electricity to starve them into submission," he said. "The reason for being here is because the Libyan people cannot reach their future on their own," Cameron said. "We are all here in one united purpose, that is to help the Libyan people in their hour of need."