(Reuters) -- Dozens of rescue boats battled strong winds, high waves and poisonous fumes to locate 31 missing sailors and tame the ship fire, amid growing concerns the ship may explode or sink, said a ministry official.

"We believe flames would last for two weeks or a month considering previous cases of oil tank accidents," said official Park Sung-Dong.

The tanker Sanchi (IMO:9356608), run by Iran's top oil shipping operator, National Iranian Tanker Co, collided on Saturday with the CF Crystal (IMO:9497050), carrying grain from the United States, about 160 nautical miles (300 km) off China's coast near Shanghai.

It was carrying 136,000 tonnes of condensate, an ultra light crude that is highly flammable and to South Korea, equivalent to about 1 million barrels and worth about $60 million.

(Photo: reuters)