The top U.S. intelligence official visited South Korea this week and met with top Seoul officials to discuss North Korean issues, officials here said Thursday.

Director of National Intelligence James Clapper arrived in Seoul on Wednesday as North Korea is set to hold its key party congress on Friday, amid lingering concern the country will conduct its fifth nuclear test.

"Clapper visited the Ministry of Defense building yesterday morning in an unofficial visit and met with Defense Minister Han Min-koo," a government official said on the condition of anonymity.

The two discussed the possibility of another North Korean nuclear test and other security issues, the official said, without elaborating.

Clapper also met with other ranking security and military officials, as well as Gen. Vincent Brooks, the new commander of U.S. Forces Korea, they said.

"The visit is believed to have been made in time for the appointment of Gen. Vincent Brooks," said another government official, noting that they are believed to have exchanged intelligence on recent developments in the North's nuclear activities.

The director formerly made an unofficial visit to Seoul in May 2014, and met with President Park Geun-hye and then-Defense Minister Kim Kwan-jin.

The officials did not provide any information on Clapper's current location. (Yonhap)