India is expanding a covert uranium enrichment plant that could potentially support the development of thermonuclear weapons, a defense research group says, raising the stakes in a regional arms race with China and Pakistan.

The revelation highlights the lack of nuclear safeguards in India under new Prime Minister Narendra Modi, while sanctions-bound Iran faces minute scrutiny over its nuclear program.

New units at the Indian Rare Metals Plant would boost India's ability to produce weapons-grade uranium to twice the amount needed for its planned nuclear-powered submarine fleet, IHS Jane's said.