An ONGC helicopter carrying nine persons including two pilots, on Tuesday made an emergency landing near a company's rig in the Arabian Sea, the company said.

Four of the nine persons have been rescued so far and attempts are on to bring the others to safety, a company official said.

The helicopter, which had six ONGC personnel onboard, and one belonging to a contractor working for the company, was forced to land using the floaters that are attached to such coppers that carry personnel and material from shore to offshore installations.

The circumstances that led to the emergency landing were not immediately clear. Other details too were awaited.

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

"#Helicopter mishap in #Arabian Sea near #ONGC rig Sagar Kiran in #Mumbai High; carrying 7 passengers & 2 pilots. Four rescued. Rescue operations in full swing," ONGC tweeted.