"1 Pawanhans Helicopter of ONGC flying from Juhu, Mumbai to ODA Offshore Development Area lost at sea this morning".
Indian Coast Guard said some debris has been found and the search for missing persons is underway.
The helicopter lost contact with Air Traffic Control (ATC) at 10:35 AM.
Union petroleum minister Dharmendra Pradhan tweeted that he had requested Defence Minister Nirmala Sitharaman to provide Coast Guard's assistance in the rescue operation. According too latest report one body has been recovered so far.
The helicopter had been leased to ONGC by the state-owned Pawan Hans helicopter firm.
Among the passengers were some officials of the Oil And Natural Gas Corporation or ONGC.
"A Dornier aircraft and helicopters from Daman (near Dahanu) have also been launched", a Coast Guard spokesperson said.
No contact could be established after 10.30 AM. Meanwhile, a rescue operation to trace the remaining people is underway.
Search operations are on, they added.