The South Korean government banned the port entry of four South Korean ships confirmed to have imported North Korean coal to the country from Saturday, the Foreign Ministry said Sunday.

“The government kept four ships -- the Sky Angel, the Rich Glory, the Shining Rich and the Jin Long, which are used to transport products banned under the UN Security Council Resolution 2371 -- from entering local ports starting Aug. 11,” the Ministry of Foreign Affairs said in a text message.

The resolution, which was adopted on Aug. 5, 2017 to punish North Korea for test-firing intercontinental ballistic missiles, bans the Stalinist country from exporting coal, iron ore and other minerals.

On Friday, the Korea Customs Service said that three South Korean firms imported North Korean coal and pig iron from Russia on seven occasions between April and October last year by forging customs documents in apparent violation of a UN sanctions resolution. It asked prosecutors to indict the companies for illegally importing the mineral resources worth 6.6 billion won ($5.8 million).

The government, the official said, will report the detailed investigation results to the UN Security Council possibly within the week, adding that the United States has already been briefed on the matter. (Yonhap)