South Korea has seized a 2,900-ton cargo ship near the Korea Strait on suspicion of violating UN Security Council sanctions against North Korea, Yonhap news agency has quoted sources as saying.

The foreign-flagged freighter said to be carrying coal and iron ore with 10 crewmembers, was en route from Russia to China, supposedly via North Korea, when it was seized on Thursday.

The vessel is now anchored in Busan on the country's southeastern coast.

In late March, another 3,000-ton cargo ship, which was heading to Vladivostok, Russia, was seized in waters off Yeosu, along the southern coast on similar suspicions.