Some 4,500 tonnes of crude oil is believed to have spilled from a Japanese tanker in the Indian Ocean following a collision with a cargo vessel, the tanker's owner said on Tuesday.
The Bright Artemis with 23 people on board leaked the oil on Monday some 290 kilometres west of India's Great Nicobar island, a spokesman said in Tokyo.
The collision occurred when the Bright Artemis, sailing to Japan carrying 250,000 tonnes of crude oil from Saudi Arabia and Oman, was trying to rescue the crew of the Singaporean vessel Amar, which was on fire, he said.
"The Bright Artemis approached the vessel to try to save people on it, but accidentally the two collided," the spokesman said.
"It is difficult to calculate at this moment, but the oil leak may have hit some 4,500 tonnes," the spokesman said, adding that no one was injured in the accident.
After informing Singaporean and Indian authorities of the accident, the tanker resumed sailing to Japan, as there was no fear of sinking or further oil leakage, the spokesman said.