South Korea says it's seized a Hong Kong-registered ship that reportedly transfered oil to a North Korean vessel in October.
On Tuesday, a South Korean paper reported China had been sending oil to North Korea via ship-to-ship trades.
That would put China in violation of a United Nations security resolution from September 2017, which barred that type of oil transfer to North Korea.
South Korea says it has the ship's crew in custody while the investigation continues. China has denied it violated the resolution.
The captured vessel is 1 of 10 ships the U.S. asked the U.N. to ban from international ports earlier in December.
