Russian President Vladimir Putin has spelled out his views on security, bilateral relations and regional cooperation in a letter to U.S. counterpart Barack Obama, a Russian diplomatic source said Monday.

The letter was delivered by Putin's Kremlin predecessor Dmitry Medvedev who attended the G8 summit at Camp David at the weekend after Putin had cancelled his U.S. visit on the grounds that he was too busy picking a cabinet.

Talks between NATO chief Anders Fogh Rasmussen and Pakistani President Asif Ali Zardari were canceled Saturday as Islamabad appeared headed for a clash with the U.S. over reopening Afghan supply routes.

Both NATO and Pakistani officials insisted to AFP that the last-minute delay in the planned meeting in Chicago was due to the late arrival of Zardari's flight from London.

Iran's foreign minister told his German counterpart that Tehran seeks "serious intentions" from both sides at talks with world powers on its nuclear program, state media reported on Saturday.

U.S. President Barack Obama said Saturday that the G8 -- which includes Russia -- agreed that the political process in Syria should move forward "in a more timely fashion."

"We had a discussion about Syria, we all believe that a peaceful resolution and a political transition in Syria is preferable," Obama said, flanked by leaders of the G8 industrialized nations at a Camp David summit.

Actor and activist Sean Penn urged U.S. President Barack Obama to step up his support for Haiti as he hosted a Cannes fundraiser to help the country recover from the devastating 2010 quake.

Dubbed Carnival in Cannes, the star-studded party is being held on the sides of the Riviera filmfest jointly with Italian couturier Giorgio Armani. Proceeds will go to three aid groups: Sean Penn's J/P Haitian Relief Organization, Artists for Peace and Justice, and Happy Heart's Fund.

New French President Francois Hollande was the only foreign leader who showed up at a Group of Eight summit in Maryland wearing a tie, a fact that did not remain unnoticed by President Barack Obama.

"Francois, we said you could take off the tie," Obama noted as Hollande came walking up.

France's President Francois Hollande used his White House debut Friday to restate his intention to get French combat troops home from Afghanistan this year -- breaking with NATO's 2014 schedule.

Hollande met U.S. President Barack Obama for the first time since taking office three days ago, ahead of a testing weekend of international summits, with G8 leaders at Camp David and NATO chiefs at a 61-nation gathering in Chicago.

World leaders will huddle at Camp David Friday with the focus on Greece as it stumbles toward an unprecedented Eurozone exit that holds wildly uncertain repercussions for the global economy.

Leaders from the Group of Eight industrialized nations will gather at the history-imbued U.S. presidential retreat near Washington for a two-day summit, with the dramatic denouement of Greece's economic crisis firmly at the top of the agenda.

There is still no agreement among leaders of the world's richest nations on the final text of a declaration that will touch upon the protracted conflict in Syria, a Kremlin advisor said Thursday.

The leaders of the G8 -- Britain, Canada, France, Germany, Italy, Japan, Russia, and the United States -- will meet Friday and Saturday for a summit at the Camp David presidential retreat near Washington.

Syria's rebels have seen an influx of arms including anti-tank weaponry for their fight against President Bashar Assad regime, in an effort coordinated with the help of the United States, a report said Wednesday.

Officials in President Barack Obama's administration insist it is not directly supplying the weapons or providing funding, with Gulf states paying for the new arms, the Washington Post said, citing U.S. and foreign officials.