The tanker was carrying gasoline-blending fuel known as alkylate for Reliance Industries' U.S. unit from a refinery in Jamnagar in Gujarat state, according to the sources, who added the extent of damage was not yet known.

"It appears to have hit the peripheral structure of the single point mooring (SPM)," one of the sources said, adding that no vessel is scheduled to discharge at its SPM currently.

BPCL has a single point mooring at Sikka to import crude for its landlocked Bina refinery in central India.

RIL and BPCL did not immediately respond to Reuters' requests for comment. The sources declined to be identified because they were not authorised to speak publicly about the matter.

(Reporting by Nidhi Verma; Writing by Mohi Narayan; Editing by Jamie Freed)

By Nidhi Verma