Four persons died after a Oil and Natural Gas Corporation Limited helicopter they were travelling in made an emergency landing near a rig in the Arabian Sea, PTI reported.

There were seven passengers and two crew members on the helicopter.

The helicopter managed to stay afloat with the help of the attached floaters for some time, helping rescuers pull out all the nine persons, a company official said, according to PTI.

Four of them were unconscious and were airlifted to a Mumbai hospital where they were declared dead, the official added.

The dead have been identified as Mukesh Patel, Vijay Mandloi, Satyambad Patra and Sanju Francis, the Hindustan Times reported, citing an unidentified official.

Three of them were ONGC employees while the fourth one was hired on a contract by the oil company.

It was not clear why the chopper had to make an emergency landing even as the Indian Coast Guard said in a tweet around 1.30 pm that it crashed off the coast of Mumbai.

ONGC has several rigs and installations in the Arabia Sea that are used to produce oil and gas from reservoirs lying below the seabed.