In its "Camp David Declaration", the G-8 grouping also supported Kofi Annan's settlement plan for Syria and cautioned North Korea against further provocations, besides pledging to take steps to mitigate economic impact of Afghan transition and stressing that Greece, which is battling a crippling debt crisis, should remain in the Eurozone.
As Iran faced sanctions, the G-8 leaders said increasing disruptions in the global oil supplies "pose a substantial risk" to the world economy.
"Looking ahead to the likelihood of further disruptions in oil sales and the expected increased demand over the coming months, we are monitoring the situation closely and stand ready to call upon the International Energy Agency to take appropriate action to ensure that the market is fully and timely supplied," the joint declaration said.
At the end of a series of brain-storming sessions that began with a dinner in this US presidential retreat on Friday night, the G-8 expressed "grave concern" over Iran's nuclear programme and urged Tehran to meet the requirements of International Atomic Energy Agency's (IAEA) Board of Governors in this regard.
"We also call on Iran to address without delay all outstanding issues related to its nuclear programme, including questions concerning possible military dimensions," the declaration said, adding that the G-8 countries desire a peaceful and negotiated solution to concerns over Iran's nuclear programme, and therefore remain committed to a dual-track approach.
The G-8 comprising the US, Japan, Britain, Germany, France, Italy, Canada and Russia backed Greece and said they wanted it to remain in the eurozone. "We agree on the importance of a strong and cohesive eurozone for global stability and recovery," the declaration issued at the conclusion of their two-day meet, said.
"We affirm our interest in Greece remaining in the eurozone while respecting its commitments." President Obama said that G-8 leaders, in their summit in Camp David, agreed that growth and jobs must be their "top priority" and noted a stable, growing European economy is in everybody's best interests, including America's.
Observing that the Europe's situation is more complicated than that of the US, Obama said Europe has got a political and economic crisis facing Greece, slow growth and very high unemployment in several countries. "And what's more, when they want to decide on a way to move forward, there are 17 countries in the eurozone that need to come to an agreement. We recognise that and we respect that," he said.
The G-8 leaders also committed themselves to launching a "New Alliance for Food Security and Nutrition" in association with African and other nations, aimed at lifting 50 million people out of poverty over the next decade.
"Building on this progress, and working with our African and other international partners, today we commit to launch a New Alliance for Food Security and Nutrition to accelerate the flow of private capital to African agriculture, take to scale new technologies and other innovations that can increase sustainable agricultural productivity, and reduce the risk borne by vulnerable economies and communities," they said.