SEOUL: South Korean marines arrested an American man late on Tuesday who had been swimming in a river that flows toward North Korea and said he had been trying to go to the North to meet its leader, Korean media reported.

S. Korean marines guarding the Han river, which flows into an estuary and meets the North’s Imjin river, found the man lying on the river bank, apparently suffering from exhaustion, the South’s Yonhap news agency said, citing a S. Korean government official.

The man, who is believed to be in his late 20s or early 30s, told S. Korean authorities he wanted to get to N. Korea to meet its leader, Kim Jong Un, Yonhap said.

The two Koreas are technically still at war after their 1950-53 conflict ended in a truce and not a peace treaty. Their border is one of the most heavily militarised in the world and unauthorized bids to cross it can spark clashes.

S. Korea’s defense ministry could not immediately confirm details of the report but an official said an American man was picked up by the military late on Tuesday and was being questioned.

The US Embassy in Seoul said it had been in contact with S. Korean authorities about the report. “We do not have any additional information to share at this time. We have been in touch with the appropriate S. Korean authorities regarding the reports,” embassy spokeswoman Nida Emmons said by e-mail.

The incident comes after a young American man, Matthew Miller, was detained in the North after entering as a tourist in April. He was sentenced to six years of hard labor on Sunday for committing “hostile acts” toward the N. Korean state.

There have been no cases of Americans entering N. Korea from the South without legal authorization in recent years.

A S. Korean man was shot and killed by S. Korean soldiers in September while he was apparently trying to enter the North by floating across a border river.