The official also said the government will ban the four foreign vessels found to have carried the North Korean coal from entering the South Korean ports. The measure will take place as early as this week, the official added.

The vessels are the Panama-registered Sky Angel, the Sierra Leone-flagged Rich Glory and Belize-flagged ships Jin Long and Shining Rich. The government said those ships illegally transported coal from North Korea despite UN restrictions on such activities.

Following North Korea’s nuclear and ballistic missile tests, the UN Security Council last August barred all member nations from importing North Korean coal, iron ore and other significant sources of hard currency.

The Security Council adopted another resolution in December requiring UN member states to seize, inspect and impound any vessel in their ports and territorial waters if they have “reasonable grounds” to believe they have engaged in transporting prohibited commodities.

The United Nations recently raised concerns that North Korea is exploiting gaps in sanctions enforcement. Pyongyang has been accused of securing refined oil through illegal ship-to-ship transfers at sea and smuggling its coal abroad with the origin disguised.

According to South Korea’s Customs Service on Friday, the North Korean ship Rung Ra 2 carried 4,580 tons of coal from the North’s Daean port to the Russian port town of Kholmsk last July. Three months later, the coal was disguised as Russian products and transferred to the South Korean port city of Donghae.

By Yeo Jun-suk(jasonyeo@heraldcorp.com)