Singh is the first Indian premier in five years to visit Japan, whose conservative government has made improving ties with New Delhi a top priority to balance frequent friction with a rising China.

"Strong ties between India and Japan will be a major factor in building an open and inclusive Asia and in enhancing peace and stability in the region," Singh said in an address to a joint session of the Japanese parliament.

"Our partnership has the potential to create an arc of advantage and prosperity across Asia, laying the foundation for the creation of an Asian economic community."

Japan's ties with communist China remain strained by the legacy of its atrocities in the 1930s and 1940s, when it invaded neighboring countries in the name of creating a Greater East Asia Co-Prosperity Sphere.

But both Singh and Japanese Prime Minister Shinzo Abe, with whom he will hold talks Friday, have been trying to repair relations with China. And India, despite warming ties with the US, has long called for a "multipolar" world.

Singh is seeking Japan's blessing for a controversial India-US pact that allows civilian nuclear cooperation even though New Delhi has developed nuclear weapons.

In an aside from his prepared text, Singh told lawmakers that India's commitment to stopping the spread of nuclear weapons was "unshakable" even though it refuses to sign the Non-Proliferation Treaty.

The support of Japan, the only nation to be attacked by atomic weapons, could open the door for international nuclear cooperation with India and counter Singh's critics, who say he has conceded too much to Washington.

But Yohei Kono, the speaker of the lower house, offered a gentle rebuke as he welcomed Singh to the podium.

He thanked the Indian parliament for offering an annual silent prayer to victims of Hiroshima and Nagasaki and added: "Again we call on your country to mutually cooperate to abolish nuclear weapons."

Despite Japanese conservatives' bid to ally with New Delhi to balance Beijing, Singh did not mention China by name in his address -- other than to point out disapprovingly that it conducted more trade with India than Japan did.

"Economic ties must be the bedrock of our relationship and a strong push is required in this area. Our trade and investment ties are well below potential," said Singh, who is accompanied by a high-level business delegation.

India in 2004 replaced China as the top destination for Japan's low-interest loans, a key tool of Tokyo's diplomacy and sign of its political intentions.

But investment has not followed. Japan invested 170 million dollars in India last year, less than three percent of the amount it invested in China, according to official Japanese figures.

Japan had shown initial enthusiasm when India ended five decades of rigid protectionism in 1991. Singh, who as finance minister fathered the reforms, secured Japanese loans to end a balance-of-payments crisis.

"I return to Japan as the prime minister of a new India," Singh said, pointing to India's breakneck macroeconomic growth.

In talks with ministers Thursday, Singh sought Japanese financing for a proposed 2,800 kilometer (1,700 mile) high-speed freight railway seen as vital to improving India's creaky infrastructure.

Japan will look at the proposal once details are set, Finance Minister Koji Omi told him.