NEW DELHI -- India and China agreed Monday to form a "strategic partnership," creating a diplomatic bond between Asia's two emerging powers that would tie together nearly one-third of the world's population.
The agreement, announced during a South Asia tour by Chinese Premier Wen Jiabao, reflects a major shift in relations between the two nuclear countries, whose ties have long been defined by mutual suspicion. It also is another step in a charm offensive by Beijing, which is trying to build ties with its neighbors and ensure regional stability for economic growth.
The United States, which also has courted warmer ties with India, welcomed efforts by New Delhi and Beijing to find ways of cooperating.
"This is an important visit. We are working to promote friendly ties of cooperation between our two countries," Wen said after a ceremonial welcome by Prime Minister Manmohan Singh at New Delhi's presidential palace.
Wen also has been to Pakistan, Bangladesh and Sri Lanka in recent days, hoping to reassure its neighbors that increasing clout does not make it a regional danger.
"Some people are worried that a stronger and more developed China would pose a threat to other countries. Such worry is completely misplaced," Wen told a meeting of Asian officials in the Pakistani capital, Islamabad, last week.
But the agreement with India also underscored the power the two nations are increasingly comfortable about wielding.
"India and China can together reshape the world order," Indian Prime Minister Manmohan Singh said Monday.
Left out of the equation, for now, was the United States, which announced last month it wanted to help India become a world power. However, India and China, which together have a population of more than 2.3 billion, took care not to offend the United States on Monday.
Chinese leaders insist they're not worried about the warming U.S.-India ties, despite Washington's apparent attempts to counter China's power in Asia by boosting India's economic and political profile.
Last month, U.S. officials announced the sale of F-16 jet fighters to Pakistan and signaled that India could move ahead with its own weapon buys. India expressed "great disappointment" over the sale and said doing so would tilt the military balance in the region and could harm India-Pakistan peace talks that began last year. The sale will likely be discussed Thursday on a visit to Washington by Indian External Affairs Minister Natwar Singh.
In Washington, a State Department official said the United States welcomed the meetings between India and China, especially if they can lead to peace, prosperity and security, not only in the region but also globally.
Analysts said the agreement would not be a major concern for Washington.
"I think the U.S. doesn't have a problem" with China and India growing closer, said Teresita Schaffer, a former State Department expert on South Asia now with the Washington-based Center for Strategic and International Studies. "The U.S. should see this as a stabilizing factor in the region. ... I realize some people will interpret this in a classic balance-of-power sense, but I don't think that's how the United States is looking at it right now."
China and India, which fought a brief war in 1962 over border disagreements, sealed their agreement with the joint statement and a set of accords aimed at ending one longstanding border dispute and boosting economic ties.
"The leaders of the two countries have therefore agreed to establish an India-China strategic and cooperative partnership for peace and prosperity," the statement said.
The partnership would promote diplomatic relations, economic ties and contribute to the two nations "jointly addressing global challenges and threats," it said.
Under the agreement, China has recognized the Himalayan territory of Sikkim as a part of India, and the two reached consensus on principles leading to an overall settlement of their decades-old boundary disputes, said Shyam Saran, a top official in the External Affairs Ministry.
"A new map which the Chinese have published shows Sikkim as part of India. This is no longer an issue between us," he told reporters.
Sikkim, located between Nepal and the kingdom of Bhutan, was an independent principality before being annexed by India in 1975. China never recognized Sikkim as an Indian possession and has claimed part of the territory as its own. But in 2003, China removed Sikkim from a government Web site that showed it to be a part of China, a sign it was moving toward officially recognizing the area as part of India.
India says China still holds 16,000 square miles of its territory in the Kashmir region, while Beijing lays claim to a wide swath of territory in India's northeastern state of Arunachal Pradesh, which shares a 650-mile border with China's Tibet region.
Monday's talks also resulted in a raft of agreements for cooperation in such diverse areas as civil aviation, finance, education, science and technology, tourism and cultural exchanges.
China, which is one of five members of the 15-nation U.N. Security Council with veto power, also signaled its support for India's quest for a seat in an expanded version of the powerful body.
Both countries have been seeking to expand their influence as their economic power has grown. But Beijing, in particular, has been on a diplomatic initiative.
In the last week, Wen signed a cooperation treaty with Pakistan promising to help it resolve disputes with India. China is already Pakistan's main trading partner and a major military backer.
A day later, Wen was in Bangladesh, signing accords to help the poverty-ridden country. From there he flew to Colombo, offering to help Sri Lanka rebuild harbors, roads and other infrastructure destroyed by the December tsunami.
The diplomatic offensive is rooted in two things China desperately wants abroad: resources and tranquility.
China is already the world's No. 2 oil importer, and its appetite for all sorts of industrial raw materials is growing, sparking such agreements as oil and gas deals with Venezuela, Kazakhstan, Qatar, Australia and Russia. On Monday, Indian officials suggested the two nations cooperate for the world's shrinking energy resources.
"A bidding war does not help either India or China," Saran said. In oil-rich Central Asia or Africa, "Indian and Chinese oil consortiums could work in tandem."