Group of Eight leaders agreed in their initial discussions at Camp David on Friday that Iran needs to disclose more about its nuclear ambitions and that it was time to focus on a political transition in Syria, a US official said.
The leaders also stressed the importance of having North Korea adhere to international norms with its nuclear program and said it would face more isolation if it "continues down the path of provocation," the official said.
The Friday evening dinner, hosted by US President Barack Obama, was the first opportunity for the G8 leaders to discuss global security concerns. They will talk about the euro zone crisis and other economic issues, including oil market pressures at the summit on Saturday.
The US official also described "a sense of optimism" about conditions in Myanmar, and said the leaders gathered at Camp David, in the Maryland countryside, pledged to cooperate on providing aid to the former Burma.
New French President Francois Hollande, participating at the G8 summit for the first time, demonstrated "good unity" related to Iran, as did Russian Prime Minister Dmitry Medvedev, according to the official.
The Camp David summit comes days before the next round of Iran talks, to be held in Baghdad. The G8 leaders "affirmed the importance of having a uniform effort in approaching those Baghdad talks next week," the US official said.
"Each of the leaders noted the urgency for Iran to take concrete steps to assure the international community of the peaceful purpose of its (nuclear) program," the official said.
On the crackdown by Damascus, the official described broad agreement on "the need to move rapidly toward a plan for political transition within Syria."