SEOUL (AFP) - South Korea Thursday criticised an "unhelpful" visit to North Korea by a senior aide to Japan's prime minister, saying it weakened the united front needed to deal with Pyongyang.
Mr Isao Iijima arrived in Pyongyang on Tuesday on a visit that clearly surprised both Seoul and Washington, which have been working closely with Tokyo on coordinating North Korea policy.
South Korean Foreign Ministry spokesman Cho Tai Young said it was "important" that the US and its two close allies continue to work in tandem.
"In that sense, we think that the visit by Iijima to North Korea is unhelpful," Mr Cho said.
Japanese Prime Minister Shinzo Abe has refused to comment on the purpose of Iijima's trip.
But Mr Abe said that he would consider meeting North Korean leader Kim Jong Un if it could help resolve the longstanding issue of Pyongyang's kidnapping of Japanese citizens.
The North's state media said Mr Iijima held talks on Wednesday with Mr Kim Yong Il, secretary of the ruling Workers' Party Central Committee.
Mr Iijima was also a senior aide to Japan's then-prime minister Junichiro Koizumi, and is known to have played a role in organising his trips to Pyongyang in 2002 and 2004 for talks with then-North Korean leader Kim Jong-Il.
Mr Iijima's visit fuelled speculation that the North may be trying to thaw icy relations with Japan at a time when ties with the United States and South Korea have gone into deep freeze after nuclear and missile tests.
The US, along with its two Asian allies, has increased pressure on Pyongyang to drop its nuclear ambitions and to join the international community.