A North Korean ship impounded in the Philippines last week was registered as being from Sierra Leone via a practice called flag of convenience, South Korea said Sunday.

Flag of convenience is a business practice of registering a merchant ship to a country other than its origin for the purposes of avoiding taxes and other regulations.

The Philippines seized the North Korean ship Jin Teng on Saturday, becoming the first country to enforce sanctions on the reclusive country since the United Nations Security Council passed a more comprehensive resolution last week.

Resolution 2270 subjects 31 ships belonging to North Korea's Wonyang Shipping Corp. to an asset freeze and sanctions.

Despite being Sierra Leone-flagged, the Jin Teng was seized because the sanctions are imposed via the ship's International Maritime Organization number, not its country of origin, a South Korean official said.

Nine other ships on the list are registered as being from countries other than North Korea, including Tanzania and Cambodia, the official added. (Yonhap)