India approved on Wednesday plans to construct two of a new class of nuclear-powered attack submarines, two defence officials said, in a project estimated to cost about 450 billion rupees ($5.4 billion).

As India scrambles to modernise its military in the face of China’s growing presence in the Indian Ocean region, it is focusing on boosting naval capabilities, and improving domestic weapons-making capacity.

Prime Minister Narendra Modi’s cabinet gave the go-ahead for the first two submarines of a new class of six the Indian Navy plans to make, the officials added, speaking on condition of anonymity, but stopped short of providing delivery dates.

China, the world’s largest naval force, with more than 370 ships, has been a security concern for India since ties nosedived in 2020 after 24 troops died in clashes along their Himalayan frontier.

Faster, quieter and capable of longer underwater stays than conventional diesel-powered craft, which makes them more difficult to detect, nuclear-powered attack submarines rank among the most potent naval weapons in the world.

Only a handful of nations make them now, such as China, France, Russia and the United States.

India, which leased two nuclear-powered attack submarines from Russia in the past but since returned them, has been in talks with it to lease another.

The new submarines will be built at the government’s shipbuilding centre in India’s southern port of Visakhapatnam. Construction major Larsen and Toubro is also expected to join the project, one of the sources added.

They will be different from the Arihant-class nuclear-powered submarines India is now building, capable of launching nuclear weapons, the second of which was commissioned in August.