South Korean authorities on Tuesday detained a North Korean boat carrying people believed to be seeking to defect from the isolated country, the military said.

The small, wooden vessel was stopped off South Korea's eastern city of Sokcho after being spotted near the Northern Limit Line, the de facto sea boundary between the two Koreas, early on Tuesday, the Joint Chiefs of Staff said.

The military did not disclose how many people were aboard, but Yonhap news agency said four North Koreans were on the vessel and had expressed their intent to defect.

It is the second known case of North Koreans crossing the sea border to seek defection in recent months, after nine people crossed the western sea boundary on a fishing boat in May.

Most North Korean escapees make their way through China and Southeast Asia, rather than attempting to cross the heavily guarded border between North and South Korea.

In 2019, South Korea deported two North Korean fishermen suspected of murdering 16 shipmates aboard their vessel while crossing the sea border. This month, South Korea said it had protested to China over the suspected forced repatriation of a large number of North Koreans, who rights groups say face imprisonment and abuse at the hands of North Korean authorities.

A Chinese foreign ministry spokesperson said at the time there were no "so-called defectors" in China, when asked about a report Beijing had deported about 600 North Korean defectors.