An adviser to Japanese Premier Shinzo Abe held a meeting with North Korean officials in China in October, a news report said Tuesday, kindling speculation that Tokyo is seeking to reopen talks with Pyongyang over the issue of Japanese abductees.

In response to the Kyodo News report, South Korea cautioned against any unilateral move by Japan regarding Pyongyang.

“Japan’s talks with North Korea should be conducted in close communication and coordination with South Korea and the United States,” Foreign Ministry spokesman Cho Tai-young said in a briefing, adding that the government is still verifying the report.

The four-day visit by Isao Iijima was made to the northeastern port city of Dalian, where the two sides had met for covert negotiations in the past, Kyodo said, citing diplomatic sources in Beijing.

The latest trip coincides with the pending sale of the headquarters of the General Association of Korean Residents, a Tokyo-based pro-North Korea group better known as Chongryon. Though a Mongolian firm won the bid for the property on Oct. 17, a Tokyo court rejected it, saying its documents were not “trustworthy,” the news outlet added.

But the meeting’s main focus was likely to have been the issue of Japanese nationals kidnapped by the North decades ago, observers say.

After Iijima traveled to Pyongyang last May, he advised Abe to pursue talks with North Korean leader Kim Jong-un. The nationalist premier has displayed his resolve to tackle the long-festering issue since taking office in December 2012.

Iijima was a top aide to former Prime Minister Junichiro Koizumi and accompanied him on his two trips to Pyongyang in 2002 and 2004 for summits with late leader Kim Jong-il.

During the landmark talks, Kim admitted that North Korean agents had kidnapped 13 Japanese citizens in the 1970s and 1980s. Five of them were sent home shortly after the talks.

Pyongyang claims the eight others have died, while Tokyo has been demanding more information on them and others, who are believed to have been taken to the communist country to teach the Japanese language and customs to spies.

Kyodo also said earlier that Junichi Ihara, director general for Asian and Oceanian affairs at the Japanese Foreign Ministry, and other two officials met with three working-level North Korean officials in Hanoi from Jan. 26-27. Tokyo’s Chief Cabinet Secretary Yoshihide Suga denied the report.

But any sudden progress in Pyongyang-Tokyo relations will likely be a burden for Seoul and Washington, which have prioritized three-way cooperation on the North Korean issue. The four countries are part of a now-dormant six-nation forum on the denuclearization of the reclusive state.

Ties between South Korea and Japan have also been strained by the Abe administration’s increasingly hawkish stance on historical and territorial issues.

Iijima’s surprise trip last year prompted South Korea and the U.S. to express discomfort over Japan’s failure to inform them in advance. Seoul’s Foreign Ministry openly said the visit was “unhelpful.”

“If the Abe government is indeed looking for any unilateral move regarding North Korea, it will create another awkward situation for all of us,” a Seoul official said on condition of anonymity due to the sensitivity of the matter.

By Shin Hyon-hee (heeshin@heraldcorp.com)