An aide to Japanese Prime Minister Shinzo Abe returned home from a trip to North Korea on Saturday but declined to shed any light on the reason for his mysterious visit, AFP reports.
Isao Iijima, a senior adviser to Abe, was tightlipped when confronted by reporters in Beijing on his way home. "I won't accept any interview on this issue," he told reporters, according to Japan's public broadcaster NHK.
Abe said Saturday that Iijima would report back to Chief Cabinet Secretary Yoshihide Suga, Japan's top government spokesman, on the visit.
Iijima's trip 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.
South Korea dubbed the trip "unhelpful" to international efforts to forge a united front against Pyongyang, while the United States expressed its surprise.
The US, along with its two Asian allies, has increased pressure on Pyongyang to drop its nuclear ambitions and to join the international community.
The North's state media this week showed footage of Iijima holding talks on Thursday with Kim Yong-Nam, North's Korea's ceremonial head of state, according to NHK and other Japanese media.
But it was not clear what exactly the two had discussed.
Iijima was a senior aide to Japan's former 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.
Abe accompanied Koizumi on the 2002 visit.
When Koizumi visited Pyongyang in 2002, North Korea admitted its agents kidnapped Japanese nationals in the 1970s and 1980s to train spies in Japanese language and customs.
Some of those snatched were allowed to return to Japan along with children who were born in the North, but Pyongyang said the rest of them had died.
However, many in Japan believe the North is still holding some and Pyongyang's perceived refusal to come clean has derailed efforts to normalise ties.
The Yomiuri Shimbun on Saturday quoted Abe as saying that "the abduction issue is something that Japan has to take the initiative on".
It added that Abe had told Iijima "to assume a role of just listening" to North Korea during his visit, citing unnamed government sources.