LONDON — International leaders struggled to figure out an endgame Tuesday for Moammar Gadhafi's tottering regime, as British Prime Minister David Cameron accused the Libyan leader of shooting and starving his opponents into submission.

U.N. Secretary-General Ban Ki-Moon, U.S. Secretary of State Hillary Rodham Clinton, the Arab League, NATO chief Anders Fogh Rasmussen and up to 40 foreign ministers attended the talks, seeking to ratchet up the pressure on Gadhafi to quit.

In his opening speech, Cameron said the conference at London's Lancaster House would sketch out how the world could help Libya on a path to a post-Gadhafi rule.

"The reason for being here is because the Libyan people cannot reach that 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."

Cameron said Britain had received reports that Gadhafi was pounding Misrata, the main rebel holdout in the west, with attacks from land and sea, and relentlessly targeting civilians.

"Gadhafi is using snipers to shoot them down and let them bleed to death in the street. He has cut off food, water and electricity to starve them into submission," Cameron said.

Clinton said the international community must support calls for democracy sweeping Libya and its neighbors, but warned that change would not be easily won.

"Under different governments, under different circumstances, people are expressing the same basic aspirations: A voice in their government, an end to corruption, freedom from violence and fear, the chance to live in dignity and to make the most of their God-given talents," Clinton said. "These goals are not easily achieved. But they are, without question, worth working for together."

Outside the summit, about 70 protesters held pro-Gadhafi placards, sounded bullhorns and led chants of "Hands off Libya!" One placard read: "We can resolve our problems without you."

Representatives of one anti-Gadhafi group, the Interim National Council, called meetings earlier Tuesday with Clinton and British Foreign Secretary William Hague "very constructive." It was not attending the main conference.

Mahmoud Shammam, a council spokesman, outlined the group's vision for a post-Gadhafi Libya.

"The aspirations of the Libyan people are to be free, to live under a constitutional democratic system," Shammam told a press conference. "(We have) had enough of tyranny."

But he suggested the Libyans were prepared to fight their own battle. Though the international community had a responsibility to intervene and prevent "mass genocide," what comes next is up to the Libyan people, he said.

"We are not asking for any non-Libyan to come and change the regime," he told reporters.

But even nations that backed the internationally enforced no-fly zone to protect civilians in Libya are far from unanimous on what to do next.

Italy's Foreign Minister Franco Frattini said several nations are behind a proposal to swiftly end the conflict, setting out plans for a cease-fire, exile for Gadhafi and a framework for talks on Libya's future between tribal leaders and opposition figures.

Turkey, which has offered to mediate a permanent cease-fire, said the London talks should gauge international support for scenarios under which Gadhafi could go into exile.

But British Foreign Secretary William Hague said the meeting was "not going to choose Col. Gadhafi's retirement home."

"Of course where he goes, if he goes, is up to him and the people of Libya to determine," he said.

Frattini suggested earlier that several African counties could offer Gadhafi a haven, but African Union chairman Jean Ping decided not to attend the London conference.

U.N. special envoy Abdelilah al-Khatib, a former Jordanian foreign minister, is returning to Libya to hold talks with Gadhafi's regime and opposition figures. The U.S. is also sending diplomat Chris Stevens to the rebel-held Libyan city of Benghazi to meet with rebel leaders.

Hague and Clinton met with Libyan opposition envoy Mahmoud Jibril of the Interim National Council, which has pledged to work toward new presidential and parliamentary elections after Gadhafi's ouster, uphold human rights, draft a national constitution and encourage the formation of political parties.

Cameron and French President Nicolas Sarkozy, in a joint statement, said Jibril's council could play a key role in deciding Libya's future — but stressed it would likely not be the only party involved. They urged Gadhafi loyalists to seize a final chance to abandon the dictator and side with those seeking political reform.

Libya's deputy foreign minister Khaled Kaim told a news conference in Tripoli that foreign leaders had no right to attempt to impose a new political system on the country. "The Libyan people are the only ones that have the right to decide the country's future," he told reporters.

Kaim called on nations at the London talks to agree on a peace deal.

"We call upon Obama and the Western leaders to be peacemakers not warmongers, and not to push Libyans towards a civil war and more death and destruction," he said.

The London meeting was also to address disputes over the scope of NATO-led coalition airstrikes and to more clearly define the extent of cooperation between Libya's rebel groups and international military commanders.

Russian foreign minister Sergey Lavrov — who was not at the talks — says the international air campaign that began March 19 has breached the terms of the U.N. resolution that authorized the enforcement of a no-fly zone over Libya.

Cameron insists the coalition had not gone beyond its mandate, but acknowledged the impact had been to force Gadhafi's military into a retreat from a number of key towns.

Sweden, which is not a full member of NATO, said it will send up to eight JAS 39 Gripen fighter jets to help NATO enforce the no-fly zone, but said the planes cannot be used to attack ground targets in Libya.

Hadeel al-Shalchi, in Tripoli, Cassandra Vinograd and Bradley Klapper in London, Louise Nordstrom, in Stockholm, Colleen Barry, in Milan, and Luc van Kemenade in Addis Ababa, Ethiopia, contributed to this report