NEW DELHI, July 21 (Reuters) - Indian navy ships held joint exercises with US aircraft carrier Nimitz in the Indian Ocean on Monday (Jul 20), the US navy said, in a sign of growing cooperation between the two naval forces in the region.

The USS Nimitz and the USS Ronald Reagan have been deployed to the South China Sea for the second time in two weeks as China and the United States accuse each other of stoking tensions in the region.

India's relations with China have also been strained recently after a deadly clash on their disputed land border last month, prompting calls for closer security ties with the United States and its allies including Japan to balance regional security.

Rear Admiral Jim Kirk, commander of the Nimitz Carrier Strike Group, said in a statement that Monday's joint drills with the Indian navy helped improve interoperability of the two forces.

The drills were carried out near India's Andaman and Nicobar islands which sits near the Malacca Straits, one of the world's busiest shipping routes for trade and fuel, an Indian source said. India has a military base on the islands.

"While operating together, the US and Indian naval forces conducted high-end exercises designed to maximise training and interoperability, including air defence," the US navy said.

It said that the Nimitz Carrier Strike Group is currently deployed in the Indian Ocean in support of a free and open Indo-Pacific.

Later this year, India will host joint naval exercises with the United States and Japan in the Bay of Bengal and there is a proposal to invite Australia also into those exercises.

China has previously opposed such multilateral exercises in the region.