The United States expects a greater partnership with India in the South China Sea, where China has been at the centre of numerous territorial disputes with regional countries, the top US diplomat for East Asia said on Wednesday.

The United States and India declared themselves “among the closest partners in the world” last week during a state visit to Washington by Indian Prime Minister Narendra Modi and emphasized adherence to international law in addressing challenges to the maritime rules-based order, including in the South China Sea.

The US has seen a “clear and upward trend” of Chinese “coercion” in the disputed waters, Daniel Kritenbrink told Washington’s Center for Strategic and International Studies.

Asked whether India would have a growing role in the South China Sea and greater cooperation with the US there, Kritenbrink said “Yes,” adding that there would be greater collaboration among a group of regional powers - the US, India, Japan and Australia - known as the Quad.

He said the US focus in the region was on building capacity of allies, partners and friends that share a vision for a peaceful and stable world.

“We will welcome cooperation with any country that embraces that vision. That of course includes India,” Kritenbrink said.

“Large countries should not bully smaller ones,” he added, referring to China’s disputes with other South China Sea claimants.

Tensions are high in contested parts sea, one of the world’s most important trade routes and a conduit for more than $3 trillion of annual ship-borne commerce.

China claims almost the entire sea as its territory and says disputes should be left to countries in the region to settle without outside interference.

The spokesperson for China’s Washington embassy said Beijing’s South China Sea position had a solid historical and legal basis, whereas the US was not a party to the disputes and should not be conducting military operations in the area.

“If the US really cares about the stability of the South China Sea and wants to avoid accidents, I think it needs to stop the reconnaissance operations against China,” Liu Pengyu told a news briefing.

The United States has been seeking to revive direct military-to-military contact with China to avoid misunderstandings that could lead to unintended conflict, but China has resisted this.

Though not a South China Sea claimant, India has in recent years stepped up security ties in the region, signaling its intent to play a bigger role in efforts to counter China.

India’s navy said on Wednesday it was sending an active duty missile corvette to Vietnam as a gift, the first warship it has given to any country.

Kritenbrink referred to “unsafe maneuvers” by Chinese vessels inside Vietnam’s exclusive economic zone last month, particularly in the waters around oil and gas installations.

“(China’s) provocative behavior exacerbates risks for businesses, effectively pushing out competition and paving the way for the PRC to push a joint development deal with its state owned firms,” he said.