WASHINGTON: Barack Obama threw the biggest party of his presidency for Indian Prime Minister Manmohan Singh, hailing the world's largest democracy as "indispensable" and pledging to work out a range of thorny issues.

Obama rolled out the red carpet for Singh for the first full-fledged official visit of his White House, climaxing in a black-tie dinner that was one of Washington's most elite social occasions since his January 20 inauguration.

Obama, who had caused unease in India with his early focus on neighbors China and Pakistan, assured that the world's largest democracy was a true partner on his top priorities from counter-terrorism to climate change.

"Our nations are two global leaders, driven not to dominate other nations, but to build a future of security and prosperity for all nations," Obama said, flanked by Singh. "As we work to build that future, India is indispensable."

Singh seconded that India and the United States "have a shared interest in promoting prosperity and stability in the Asia-Pacific region."

In a nod to Indian concerns about Pakistan, they later issued a joint statement voicing "grave concern about the threat posed by terrorism and violent extremists emanating from India's neighborhood."

Obama accepted an invitation to visit India next year and his administration signed eight memoranda aiming to solidify growing cooperation.

One 10-million-dollar initiative named after Obama and Singh would support university linkages; India is already the top source of foreign students in the United States.

The two nations also agreed to launch a dialogue on economic relations, with Treasury Secretary Timothy Geithner to head to India in early 2010.

Other projects would work to boost food security and support research on green technology, with two dozen cities across the United States and India to test new systems on solar technology.

Climate change has been one of the few points of recent discord between India and the United States, with each side pressing the other to make further commitments ahead of next month's high-stakes Copenhagen summit.

But Obama, who is expected to make an announcement in coming days on a target for US cuts in carbon emissions, said he agreed with Singh and Chinese leaders to reach a "strong operational agreement" on reducing global warming.

"It takes us one step closer to a successful outcome in Copenhagen," Obama said.

With a cold drizzle covering Washington, the White House called off an elaborate welcome on the South Lawn but went ahead with a glittering dinner for several hundred guests for which invitations were a coveted prize.

Besides the top brass of US politics, guests included Hollywood mogul Steven Speilberg and members of the increasingly influential 2.5-million-strong Indian-American community.

"You are the hottest ticket in town," Vice President Joe Biden told Singh at a lunch he co-hosted for the premier with Clinton.

Showing the new president's style, his wife Michelle Obama served fresh arugula grown at a White House garden she set up in a drive to encourage better eating habits.

The White House tapped Ethiopian-born, Swedish-raised chef Marcus Samuelsson, whose cuisine is renowned for transcending cultural barriers, as the guest chef.

In deference to many Indians' dietary preferences, the menu was almost entirely vegetarian.

The entertainment for the night was to feature two Oscar-winners -- Jennifer Hudson, the singer and actress from "Dreamgirls," and A.R. Rahman, the composer of music for "Slumdog Millionaire."

The pageantry comes one week after Obama paid his maiden visit to China, where he faced criticism at home for a lack of concrete achievements, with Chinese state television not even broadcasting his sole public forum.

India, by contrast, has transformed in a matter of years in US eyes. After decades of mutual unease during the Cold War, ties with the United States have been rapidly warming and enjoy strong support across party lines.

Former president George W. Bush signed a landmark accord with Singh to allow cooperation on civilian nuclear technology, ending New Delhi's long pariah status for declaring itself a nuclear weapons state.

Obama is a strong advocate of nuclear disarmament and many Indians doubt he would have reached the same agreement. But Obama pledged to go ahead with the deal.

"I am confident and I have the assurance that that process can be completed without much further loss of time," Singh said.