PORT BLAIR, July 15

One by one, the four Indian warships cruised into a sleepy harbour in the country’s remote Andaman and Nicobar islands, fresh from visiting Southeast Asian capitals and conducting exercises in the disputed South China Sea.

The arrival of the warships at Port Blair earlier this month symbolises how an island chain better known for its beaches and diving is quietly becoming a key plank in New Delhi’s strategy to counter China’s growing naval presence in the Indian Ocean.

In interviews in New Delhi and Port Blair, the archipelago’s administrative hub, Indian defence officials outlined plans to transform a modest military base into a strategic listening post with strengthened air force, navy and army capabilities.

While some of the officials noted that earlier expansion plans had largely faltered, they said there was fresh energy under Prime Minister Narendra Modi, who wants to reassert New Delhi’s traditional dominance of the Indian Ocean.

All agreed the chain’s location was its biggest asset in watching China’s navy.

Scattered between the Bay of Bengal and the Andaman Sea, the Andaman and Nicobar islands are closer to Myanmar and Indonesia than the Indian mainland. More importantly, its southern isles lie near the top of the Malacca Straits, a gateway to the Indian Ocean and through which China gets three-quarters of its oil.

“The world’s busiest shipping lanes are just to the south,” Lieutenant Governor A K Singh, a former military commander who runs the Andamans, told Reuters from his hill-top office in Port Blair, a one-time British penal colony.

“For too long we have had a fortress mentality about the islands, that they had to be defended. The time has come for us to start looking at these very strategically placed islands as a springboard for India.”

More recently New Delhi has worried about Chinese submarines venturing into the Indian Ocean.