South Korean soldiers arrested a U.S. citizen Tuesday night after he attempted to swim across the Han River into North Korea, media reports said Wednesday, citing a South Korean defense official. The South's Yonhap news agency reported that the man wanted to go to North Korea to meet leader Kim Jong Un.

The man was reportedly found lying exhausted on the river bank, near the Korean Demilitarized Zone, which is part of a restricted military area on the border between the two countries, the official said. According to The Associated Press, the official also revealed that investigators are questioning the man, who was reportedly in his late 20s or early 30s, about the reason behind his apparent attempt to enter the North. The identity of the man remains unclear.

“The American man was swimming northward with the current when he grew tired and laid low near the riverside. This was when he was discovered by the Marines,” a source told the Korea Herald. “I believe this is the first time an American has tried to flee to the North in the Gimpo area.”

The incident comes two days after one of the three Americans detained in North Korea was sentenced to six years of hard labor by the hermetic country for committing “hostile acts” toward the state. Matthew Miller from Bakersfield, California, who is in his mid-20s, was detained after he entered the North as a tourist in April. According to reports, incidents involving Americans attempting to enter North Korea from the South are unusual.

In September 2013, South Korean soldiers had shot dead a man who tried to swim across a river to North Korea. Officials reportedly said at the time that the man had ignored several warnings to turn back.

The two Koreas have been in a state of war after the 1950-53 conflict ended in an armistice.