Thirteen dead after naval vessel hits boat off Mumbai

At least 13 people have died after an Indian naval boat collided with a passenger ferry with more than 100 passengers which then capsized off the coast of financial capital Mumbai, officials say.

The navy said 99 people were rescued with efforts ongoing for others.

"An Indian Navy craft lost control while undertaking engine trials in Mumbai Harbour due to engine malfunction. As a result, the boat collided with a passenger ferry which subsequently capsized," the navy said in a statement on X.

Local TV channels showed a boat carrying at least five people hitting the passenger vehicle, causing the accident.

"The speedboat crashed into our boat and water started entering our boat and it overturned. The driver asked us to wear life jackets," a passenger on board the vessel told ABP Majha news channel.

"I swam for fifteen minutes before I was rescued by another boat," said the passenger, who did not identify himself.

"The boat mishap in Mumbai is saddening. Condolences to the bereaved families," India's Prime Minister Narendra Modi said in a post on X late on Wednesday.

Modi also announced an ex-gratia payment of 200,000 rupees ($A3,700) from the Prime Minister's National Relief Fund for the next of kin of each deceased in the boat accident and that the injured would be given 50,000 rupees.

The privately-owned passenger boat, called Neelkamal, was heading towards the Elephanta caves, a popular tourist destination off the coast of Mumbai, when it capsized, BMC said.

The caves, which attract a steady stream of tourists through the year, are a UNESCO heritage site and were constructed in the 5th-6th centuries AD.

Boats from the Gateway of India, Mumbai's southernmost point, make regular trips to ferry tourists to the site, an hour away.