BEIJING (Reuters) - At least ten North Korean ships have arrived at a Chinese port after being stranded for the past three weeks following the top global coal consumer’s ban on imports of the fuel from its isolated neighbor, a report said on Friday.

Six North Korean merchant vessels, including Sai Nal 3 and Jin Hung, entered the port of Longkou in China’s eastern Shandong province as of Thursday, South Korean news agency Yonhap reported on Friday, citing a Voice of America report.

Reuters ship tracking data shows that Sai Nal 3 from North Korea has been moored at the port for at least the past three weeks. It is listed at maximum draft, meaning it is likely fully laden with cargo.

Another four North Korean ships arrived at the same port on Thursday morning before heading back to the North Korean port of Nampo, Yonhap also reported, citing Voice of America.

Beijing said last month it would ban coal shipments from North Korea, starting Feb. 19, as part of its efforts to implement United Nations sanctions against Pyongyang.

It’s not clear what the vessels were carrying.

The vessels had previously been holding some 10 kilometers out from Longkou port in international waters since the Chinese ban took effect, Yonhap news reported, citing VOA.