Updated

South Korea says it inspected a Hong Kong-flagged ship that allegedly violated U.N. sanctions by transferring oil to a North Korean vessel in October.

An official from Seoul's Foreign Ministry said Friday that the Lighthouse Winmore is believed to have transferred about 600 tons of refined petroleum products to the North Korean ship in international waters on Oct. 19 after leaving the South Korean port of Yeosu.

The official says South Korean authorities boarded the ship and interviewed crew members after they returned to Yeosu on Oct. 24.

The U.S. Treasury Department last month sanctioned six North Korean shipping and trading companies and 20 of their vessels, and published photos of what it said was a North Korean vessel on Oct. 19 possibly transferring oil to evade sanctions.