French President Nicolas Sarkozy has urged Libya's Col Muammar Gaddafi to step down as "all options are open".
"We are not saying that Gaddafi needs to be exiled. He must leave power and the quicker he does it, the greater his choice," Mr Sarkozy told journalists.
He is hosting a meeting of leaders from the G8 group of wealthy nations in the northern French resort of Deauville.
The Arab uprisings, internet regulation and future of nuclear power are all being debated at the two-day summit.
The global economy and climate change are also being discussed at the gathering for the leaders of the US, Russia, the UK, France, Germany, Italy, Japan and Canada.
Thousands of police have been deployed as part of a huge security operation and checkpoints have been erected on all roads leading to Deauville.
UK Prime Minister David Cameron, also at the G8 summit, has approved the deployment of Apache attack helicopters in Libya, the BBC has learned.
There had been speculation about the move after France said it would be deploying French Tiger helicopters.
Mr Sarkozy defended Nato's intervention in Libya when he spoke to journalists on Thursday evening, saying "had we not stepped in [the rebel stronghold of] Benghazi would have been wiped off the map".
He thanked Russia for not blocking the UN resolution authorising force despite Moscow's misgivings, and said Russian President Dmitry Medvedev understood that "the blame lies with Col Gaddafi" and he had said so "frankly and unambiguously".
He said the later Col Gaddafi stood down, "the shorter the list of his possible destinations".
If Col Gaddafi stepped down and withdrew his forces quickly, President Sarkozy said, "all options are open".
"Then we'll look at what the name should be on the plane ticket and even what class he should travel," he joked.
In other remarks, Mr Sarkozy said:
- The violence used to crush pro-democracy protests in Syria was unacceptable and would be the subject of further talks at the summit
- New rules on trade and the environment were needed to recognise emerging nations. Mr Sarkozy insisted France had supported a drive to give developing nations a greater voice in the International Monetary Fund (IMF) despite Paris's backing for another European to go at its helm
- There should be a new push for peace between the Israelis and Palestinians and Europe and Russia should play a critical role along with the US in forging it
Mr Cameron has also talked about "turning up the pressure" on Col Gaddafi but the Apache helicopters will probably go into operation "within days" rather than overnight, says BBC political editor Nick Robinson.
Correspondents say recent events such as uprisings in the Arab world and Japan's nuclear crisis have given the G8 a new sense of purpose.
Interim prime ministers from Tunisia and Egypt - where long-time leaders were overthrown this year - and the head of the Arab League will also be at Deauville for talks on a massive aid plan to help their transition to democracy.
Range of discussions
As the summit opened, the French and Russian leaders met to agree the sale of four French-built Mistral helicopter carriers to Russia at a cost of at least 400m euros each (£350m; $565m).
Leaders debated ways of improving global nuclear safety after the breakdown of Japan's Fukushima power plant following March's earthquake and tsunami, with Mr Sarkozy insisting that "when it comes to nuclear matters, safety must prevail over cost - that we all agreed on".
His wife, Carla Bruni-Sarkozy, who is hosting the leaders' spouses, greeted them in a white dress that showed off her pregnancy.
US President Barack Obama, who headed to the meeting after a state visit to the UK, is holding a series of one-on-one meetings with leaders including President Sarkozy and Japanese Prime Minister Naoto Kan.
He has already met Russian President Dmitry Medvedev for discussions over the two countries' long-running row over US plans to create a missile defence shield in central and eastern Europe.
President Obama told reporters that the two men were committed to finding an approach that met the security needs of both countries, while Mr Medvedev said the two could work together towards a resolution, but it was unlikely to come in the near future.
Points of friction
BBC diplomatic correspondent Bridget Kendall, in Deauville, says that despite President Obama's appeal in London on Wednesday for democratic unity and leadership, there may well be friction at the summit.
She adds that Russia's president has opposed air strikes on Libya from the start, though he may offer to mediate in that conflict.
Africa will also be represented at the summit, as it has been since 2003. Newly elected leaders from Ivory Coast, Niger and Guinea are expected to participate in sessions about promoting democracy.
A shift in global influence to emerging powers such as India and China, who are not in the G8, has led to the bloc's relevance being questioned.
But speaking in London on Wednesday, President Obama rejected arguments that the rise of superpowers like China and India spelled the demise of American and European influence in the world.
After the summit ends on Friday afternoon, President Obama is scheduled to travel to Poland, the last stop on a four-country tour of Europe that began on Monday in Ireland.