Washington, June 14  The India-US relationship is now "stronger" than it may ever have been, The New York Times said in an editorial on Tuesday, praising the "deepened" partnership for finding a common cause to counter China's aggression in the region.

The newspaper reflected on Prime Minister Narendra Modi's recent trip to America -- his fourth in the last two years of being in power -- during which he met President Barack Obama and addressed the US Congress.

It said the Obama-Modi meeting at the White House left many analysts "puzzled over how and why the two leaders, so different in so many ways, get along".

But added quickly that more important was how the two leaders have "significantly deepened the partnership" between the two countries.

"It may be one of Obama's most important foreign policy achievements," the Times said.

India and US ties have not been so warm always. They were testy during the Cold War. But the relationship became "warmer under Presidents Bill Clinton and George W. Bush", the newspaper recalled.

The ties "are now producing concrete gains under Obama", it said, adding the "two democracies are finding common cause in countering China's aggression in the South China Sea, resisting climate change, fighting terrorism and investing in each other's economic growth".

The newspaper also praised India's commitments to fight the global warming issue and Modi's promise "to work together to realize the potential of December's Paris treaty on climate change".

But "no less important", it said, "is the growing" military cooperation between the two nations after the US formally "recognized India as a major defence partner, making it eligible to buy some of the most sophisticated American-made weapons and technology without first having to receive a license".

It also underlined how the two countries have stepped up joint military exercises.

"If there was any doubt that a message to China was intended, Modi told Congress that India appreciated America's role in Asia and endorsed its commitment to freedom of navigation in the South China Sea, which Beijing is claiming largely as its own."

However, the newspaper cautioned, some "vital issues" needed to be worked out, "now and far into the future".

These include "the India-Pakistan-China nuclear competition that threatens the region".

"It will be up to the next president to build on a relationship that is on (a) stronger footing now than it has been for some time."