With fears growing that an oil spill in the East China Sea last month could impact marine life, reefs and fishing grounds in western Japan and Okinawa in the coming weeks, the government stepped up measures Friday to deal with what has been described by scientists as potentially one of the worst oil spills in decades.

The Cabinet Office announced Friday it had established a branch to monitor information about oil spilled by the Iranian-flagged tanker Sanchi on Jan. 14 when it collided with a cargo ship. The Sanchi was carrying 136,000 metric tons of ultra-light condensate (a mix of petroleum liquids extracted from natural gas) and had been destined for South Korea.

The central government's action comes a day after the Japan Coast Guard and Kagoshima Prefecture confirmed that black oily substances were found drifting ashore on the small island of Takarajima, which lies between Amami Oshima and Yakushima, a world heritage site famous for its ancient cedar trees.