SEOUL, Jan. 19 (Yonhap) -- South Korea is investigating about 10 companies accused of importing North Korean merchandise in violation of a ban that came into effect last year over the sinking of a warship, an official said Wednesday.

   South Korea suspended all inter-Korean trade in May last year when a multinational investigation found North Korea responsible for the sinking of the Cheonan earlier that year.

   Forty-six sailors died in the sinking in which the North denies any involvement.

   Unification Ministry spokeswoman Lee Jong-joo said in a briefing in Seoul that the authorities are questioning the companies on suspicion of violating the ban by importing marine products, mushrooms and other items from North Korea via China.

   The companies claimed that they had thought the products were from China. Lee said the government plans to step up its crackdown on imports from North Korea starting next month in an effort to reinforce the ban.

   The relations between the two Koreas remain at the worst point in years after the Cheonan sinking and the North's Nov. 23 bombardment of the South's border island of Yeonpyeong. Four people died when the North shelled the western island in an attack that the South has vowed to retaliate for.

   A joint manufacturing complex in the North Korean border town of Kaesong remains the only channel of economic cooperation between the countries that fought the 1950-53 Korean War.

   samkim@yna.co.kr
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