The leaders are discussing how to end the seemingly deadlocked Libya conflict, and their response to the revolutions in Egypt and Tunisia.

Recent events such as uprisings in the Arab world and Japan's nuclear crisis have given the G8 a new sense of purpose.

Also on the agenda is how little or how much the internet should be regulated.

Internet bosses - including Facebook founder Mark Zuckerberg and Google boss Eric Schmidt - are attending the two-day summit in Normandy.

The global economy and climate change will also be discussed at the gathering for the leaders of the US, Russia, the UK, France, Germany, Italy, Japan and Canada.

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 400 million euros each.

The elements of the deal had been agreed and "the signature will take place within a fortnight", French President Nicolas Sarkozy said.

After the summit ends on Friday afternoon, President Obama is scheduled to travel to Poland, the last stop on a four-country, six-day tour of Europe that began on Monday in Ireland.