The warship INS Sumitra "compelled the safe release" of the 19 Pakistani crew members and the Iranian-flagged Al Naeemi fishing vessel, the spokesman said, saying the rescue took place overnight Monday some 850 nautical miles (1,574 kilometres) west of the Indian city of Kochi.

A total of "11 Somali pirates" had taken the crew hostage, the navy said.

Photographs released by the navy showed commandos boarding the fishing boat at night, then standing with rifles over a group of Somali pirates, the men kneeling at their feet with their hands tied behind their backs on the ship's deck.

The rescue took place just 36 hours after India said its forces had freed 17 crew members on the Iranian-flagged Iman fishing vessel, also taken by Somali pirates.

The hijackings off Somalia have fuelled concerns about a resurgence of Indian Ocean raids by opportunistic pirates, coming on top of a separate surge of attacks launched by Yemen's Iran-backed Huthi rebels.

Huthi gunmen have launched scores of attacks in the Red Sea and Gulf of Aden targeting Israeli-linked vessels in response to Israel's war against the Palestinian militant group Hamas in Gaza.

International naval forces have been diverted north from the Gulf of Aden into the Red Sea, sparking fears that pirates will exploit the security gap, with the first successful case of Somali piracy since 2017 recorded in December.

Pirate attacks off the Somali coast peaked in 2011 -- with gunmen launching attacks as far as 3,655 kilometres (2,270 miles) from the Somali coast in the Indian Ocean -- before falling off sharply after international navies sent warships and commercial shipping deployed armed guards.