London  - US President Barack Obama swept onto the world stage at this week's summit of the world's top economic powers with a charm offensive that helped to mark the launch of a new era in American foreign relations.

Obama said he came with the intention of showing leadership by "listening and learning" during a two-day visit to London for the Group of 20 (G20) summit, which included advanced and emerging economies.

While he failed to overcome resistance to increased fiscal measures to boost global economic growth, the American president still managed to present a pop star aura at the G20 summit. At a press conference winding up his visit, Obama declared the agreement a success, marking "a turning point in our pursuit of global economic recovery."

During Obama's two-day debut on the world stage, curious onlookers lined the streets to catch a glimpse of the president's bomb-proof limousine known as The Beast, which was flown in for the visit.

At the same time, global leaders jostled for an audience with the charismatic American leader, witnessing first hand the "element of humility" Obama said he would bring to US relations with the world.

Obama also pointed to a new era for America's economic relations with the world, cautioning that the US was unlikely to return to its role as a "voracious consumer market" that would pull the world economy out of its downward spiral.

In a series of bilateral talks, Obama took first steps in mending relations that had soured under his predecessor, George W Bush.

A meeting with Russian President Dmitri Medvedev augured well for the chances of a new, improved era between the two powers, which had reached a low during Russia's military intervention in Georgia last summer.

Invited by Medvedev to Moscow, Obama elicited a smile from the Russian leader, saying he wouldn't be visiting Russia during the tough winter months.

The US and Russian leaders signed a joint statement outlining concrete steps towards a new nuclear disarmament deal, the result of weeks of frenetic behind-the-scenes negotiations.

Obama's dealings with Medvedev showed a new approach to the relationship, as senior US officials said Obama was determined to "find ways to work on common interests," whilst also being "very candid where we disagree."

Officials said Obama's strategy towards Russia was to "develop an agenda based on interests," rather than the personal style of his predecessor, considered to have played a part in the souring of the partnership.

Asked at a press conference for a catch phrase that would define US relations with China, Obama deflected the question, although a meeting with Chinese President Hu Jintao held the seeds for renewed cooperation.

The US and Chinese leaders found new avenues to work jointly to combat the global recession, just a week after disagreement between the two states had threatened to escalate over Chinese demands for a new international reserve currency to replace the dollar.

Words were immediately put to practice, and a meeting was set up between US Treasury Secretary Timothy Geithner and Chinese Vice Premier Wang Qishan, to take place very late Thursday in London.

Throughout the G20 summit, Obama squeezed in meetings with South Korea, Saudi Arabia and Indian Prime Minister Manmohan Singh, whom he praised at a press conference as a "wise and decent man" who had done a wonderful job of leading India and improving economic growth.

Singh, it transpired, had earlier shown Obama another kind of deference, when he asked the American president for an autograph to take back to India for his daughter.

Obama undoubtedly clinched the popular vote during the summit, as support staff, including medics and cleaners, stepped forward for a glimpse of the mighty man as he was ushered through the corridors of the East London conference centre.

Even the journalists covering the event suspended their trademark indifference toward celebrity, taking mobile phone snaps and jostling for prime position at the press conference ending Obama's public appearance in London.

On Wednesday evening, the Obamas' star factor was briefly eclipsed during their private audience with Queen Elizabeth.

The monarch also showed herself willing to embrace change - quite literally - as she reciprocated when First Lady Michelle Obama placed an arm around her, a gesture that raised eyebrows amongst royal observers who noted pointedly that it was a breach of protocol to touch the Queen. dpa