An adviser to Japanese Prime Minister Shinzo Abe arrived in North Korea on Tuesday in a rare surprise visit to a country with which Japan has no diplomatic ties, but the purpose of the visit was not immediately known.
North Korean state television showed the aide, Isao Iijima, arriving in Pyongyang. Japan's Kyodo news agency said he was met by Kim Chol-ho, vice director of the North Korean Foreign Ministry's Asian Affairs Department.
Iijima was a top aide to former Prime Minister Junichiro Koizumi, who visited Pyongyang for talks with then North Korean leader, Kim Jong-il, in September 2002 and May 2004.
Iijima's office was unable to confirm his whereabouts and a spokeswoman for the prime minister's office said she was not aware of the visit.
Japan's relations with North Korea have long been strained by Tokyo's worries about Pyongyang's nuclear and missile programmes and by a feud over Japanese citizens who were kidnapped by North Korean agents decades ago to help train spies.
Abe owed much of his popularity when he first took office in 2006 to his tough stance towards North Korea over the abductees.
Five of the abductees were repatriated and North Korea has said another eight died.
Japan has been pressing for more information about the eight and others it says were also kidnapped. It wants any survivors sent home.