The United States and India are discussing about assisting each other to track submarines in the Indian Ocean at a time when China has increased its assertiveness in the region, Reuters reported Sunday. Indian naval officials reportedly said they have spotted Chinese submarines on an average four times every three months in the area.

Washington and New Delhi, which already carry out joint naval drills, are expected to conduct talks on anti-submarine warfare (ASW), a branch of underwater warfare where allies share sensitive military technology and closely held tactics.

“These types of basic engagements will be the building blocks for an enduring Navy-to-Navy relationship that we hope will grow over time into a shared ASW capability,” a U.S. official told Reuters.

The joint exercises will be held in the northern Philippine Sea in June and concentrate on anti-submarine warfare, an Indian naval source told the news agency.

India and the U.S. both use the latest version of the P-8 aircraft — Washington’s most advanced submarine-tracking weapon — making information sharing simpler on highly sensitive submarine-tracking activities.

Hua Chunying, a spokeswoman for China’s foreign ministry, told Reuters that Beijing had taken note of the fact that countries in the region were involved in military cooperation.

“We hope that the relevant cooperation [between India and U.S.] is normal, and that it can be meaningful to the peace and stability of the region,” Hua said.

Last month, India and the U.S. announced plans to share military logistics. India reportedly delayed the agreement over concerns that the deal could turn into a military alliance with the U.S., undermining its traditional autonomy. But Indian Prime Minister Narendra Modi’s administration has indicated interest in a flourishing relationship with the U.S. amid China’s assertiveness in the Indian Ocean. China is also an ally of India’s main rival, Pakistan.