The United States warned Tuesday of China's "threats to security" as Secretary of State Mike Pompeo and Defense Secretary Mark Esper held top level talks in India. 

The two countries are also due to complete an accord on sharing sensitive data in a new sign of their strengthening strategic ties.

"Today is a new opportunity for two great democracies like ours to grow closer," Pompeo said as he and Esper began talks with India's External Affairs Minister Subrahmanyam Jaishankar and Defence Minister Rajnath Singh. 

Pompeo outlined a series of issues of mutual concern that would be discussed.

"Our cooperation on the pandemic that originated in Wuhan, to confronting the Chinese Communist Party's threats to security and freedom, to promoting peace and stability throughout the region," he said.

Esper said the United States wanted stronger ties with India -- currently involved in a tense border showdown with China -- "to meet the challenges of the day and uphold the principles of a free and open Indo-Pacific well into the future."

Pompeo and Esper had already called for a deeper relationship during one-on-one talks with their Indian counterparts on Monday.

Jaishankar tweeted after his meetings with Pompeo that relations between the emerging allies have "grown substantially".

- Spy data accord -
An intelligence-sharing accord is also set to be signed by the two countries later Tuesday.

The Basic Exchange and Cooperation Agreement will allow the United States to share top-secret satellite and sensor data that would help India in targeting its missiles and placing troops.

It will also allow the United States to provide the latest navigational technology on any fighter jets it supplies to India. 

Esper has been pressing the case for India to buy US F-18 jets and move away from its reliance on Russian weaponry. 

But India wants more of its military equipment made domestically and is demanding greater investment.

Esper and Singh "welcomed the expansion of information-sharing", a US statement said, while the Indian Defence Ministry reported the two officials had discussed "potential new areas of cooperation", without giving details.

Relations with China have grown increasingly tense for both the United States and India in recent years.

The United States is in a tense trade battle with China and President Donald Trump's administration has stepped up warnings about Beijing's growing economic and military power.

India has sought greater international military support since a deadly border showdown with China in June. 

At least 20 Indian soldiers were killed in the clash. China has acknowledged it also suffered casualties but has not provided details.

Both sides have since sent tens of thousands of troops to their disputed frontier in the Ladakh region and are digging in for a long, hard winter in the freezing high-altitude region. 

India is shopping for US cold-weather equipment, officials said, and has also since agreed to expand naval manoeuvres in the Indian Ocean next month to include Australia. 

Traditionally, the MALABAR exercises have involved India, the US and Japan.

US officials have said they want the four-nation so-called "Quad" alliance to be given a more permanent structure, in moves that China's foreign ministry said it had "noted".

Following talks in India, Pompeo will go on to Sri Lanka, the Maldives and Indonesia. China's growing investment and influence in Sri Lanka and the Maldives have sparked concern in both the US and India.

Meanwhile, China warned the United States not to "coerce and bully" Sri Lanka ahead of a visit Tuesday to the strategically-placed island by US Secretary of State Mike Pompeo.

Pompeo is expected to ask Colombo to make "difficult" choices on its blossoming relationship with Beijing during his visit. "We are firmly opposed to the United States taking the opportunity of the State Secretary's visit to sow and interfere in China-Sri Lanka relations, and to coerce and bully Sri Lanka," China's embassy in Colombo said.

The top US diplomat for South Asia, Dean Thompson, said at the start of Pompeo's four-nation tour of Indian Ocean nations -- India, Sri Lanka, Maldives and Indonesia -- that he will ask Colombo to review options offered by Washington. 

The US visit comes less than three weeks after Yang Jiechi, a Chinese Community Party politburo member, pledged more economic help to Sri Lanka during a visit. 

Colombo has leaned heavily on China for loans and diplomatic support to fight off allegations of human rights violations, particularly in the final months of a brutal decades-long civil war.

Washington has insisted on credible investigations into charges that Sri Lankan troops killed at least 40,000 civilians while crushing Tamil Tiger rebels in 2009. 

President Gotabaya Rajapaksa was the island's top defence official and his brother Mahinda was president when the final onslaught was carried out. Mahinda is now prime minister.

Pompeo is expected to raise rights issues when he meets the Rajapaksas Wednesday in Colombo which is under a partial lockdown because of a surge in coronavirus infections.

He is also to place a wreath at St Anthony's church where 56 people were killed when jihadists carried out coordinated suicide bombings last year. Five Americans were among 279 people killed in the Easter Sunday attacks on three churches and three hotels.