Japan engaged in several informal contacts with North Korea this spring, sources close to the matter said Friday, apparently to seek a breakthrough in a longstanding impasse surrounding the abduction of Japanese nationals in the past.

Japanese Prime Minister Fumio Kishida has aimed for a summit with North Korean leader Kim Jong Un, but apparently no progress has been made, the sources said. The two nations have no diplomatic ties.

Regarding media reports that Japanese officials contacted the North Korean side in March and May, Kishida told reporters Friday that he would "refrain from making comments due to the nature of the matter."

Foreign Minister Yoko Kamikawa and Chief Cabinet Secretary Hirokazu Matsuno, who doubles as minister in charge of the abduction issue, similarly did not clarify its veracity during their separate press conferences on Friday.

The issue of North Korea's abductions of Japanese nationals in the 1970s and 1980s has become increasingly pressing, given that many of the family members of those missing are aging.

At an event in Tokyo in May seeking the return of Japanese abductees, Kishida expressed his eagerness to meet with Kim to settle the issue and pledged to set up high-level bilateral negotiations with North Korea under his "direct control."

A Japanese diplomatic source said, "It's a rule not to say what actually happened," implying there was some type of contact between the two countries.

The Japanese government has officially identified 17 of its citizens as having been abducted by North Korean agents and suspects Pyongyang was involved in many more disappearances.

In September 2002, then Prime Minister Junichiro Koizumi visited Pyongyang and signed a historic declaration with Kim's father and then-leader Kim Jong Il.

Under the Pyongyang Declaration, the two Asian countries agreed to make "every possible effort for an early normalization of relations," while Japan vowed to extend economic cooperation to North Korea after the normalization of ties.

Koizumi also drew North Korea's first formal apology for the abductions and five abductees were brought back to Japan in the following month.

Japan continues to seek the return of the remaining 12 abductees.

But North Korea has maintained that the abduction issue has been settled, and the challenge of setting up talks to resolve the abduction issue is seen increasing due to changes in the regional security environment.

In August, Kishida confirmed at a trilateral summit with the United States and South Korea that they would strengthen security cooperation, with North Korea and China in mind.

North Korea has aligned with China in its criticism of Japan's release of treated radioactive water from the crippled Fukushima nuclear power plant into the sea. It has also aligned with Russia, whose relations with Japan have soured following its war on Ukraine.

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