Indian navy and coast guard helicopters have rescued 30 crew members from a sinking cargo ship off the coast of Mumbai.

Military officials said Thursday that the vessel sent out a distress signal and the authorities immediately began operations to rescue the crew of Indonesian, Jordanian and Romanian nationals.

It is unclear why the ship was sinking.

The cargo vessel was carrying coal and was en route to the western Indian state of Gujarat when it ran into trouble off the coast of India's financial hub.