As tension mounts worldwide over the standoff concerning Iran's nuclear ambitions, Japanese oil companies are starting to take precautions as uncertainties surrounding the situation may force them to stop importing oil from the Islamic state.

On Wednesday, Nippon Oil Corp. said it will reduce its oil imports from Iran to 120,000 barrels a day from 142,000 a day in 2005 and purchase from other countries. It was the first such announcement by a firm in an industrialized nation.

Nippon Oil's move came as negotiations intensify in the U.N. Security Council over the drafting of a resolution that denounces Tehran's uranium enrichment activities, which many countries suspect are a cover for making nuclear weapons.