Foreign Minister Taro Kono said Friday that he briefly spoke with his North Korean counterpart Ri Yong Ho in Singapore in an apparent attempt to pressure Pyongyang on the abduction issue.

As Prime Minister Shinzo Abe is willing to hold direct talks with North Korean leader Kim Jong Un, Kono has been “urged” to make contact with Ri on the sidelines of the Association of Southeast Asian Nations’ gatherings in the city, a government source said.

In the wake of the historic summit between Kim and U.S. President Donald Trump in June in the city-state, Abe has been exploring the possibility of a summit with Kim.

Relations between Tokyo and Pyongyang, however, have been worsening over the abduction issue, which Abe has placed high priority on.

Japan officially lists 17 citizens as abduction victims and suspects North Korean involvement in many more disappearances. North Korea insists the issue has already been resolved.

Abe had reiterated in recent years, back when North Korea was still ratcheting up tensions, that maintaining “pressure” on Pyongyang is vital to compel it to discard its nuclear weapons and ballistic missiles.

But he has been forced to withdraw his signature policy as other major countries — including the United States, China and South Korea — have started to emphasize the importance of holding talks with the North to achieve denuclearization.

Since March, Kim has held summit talks with Chinese President Xi Jinping, South Korean President Moon Jae-in and Trump in a successive manner.

As Kim is expected to meet with Russian President Vladimir Putin in the near future, Abe is likely to become the only leader in the long-stalled six-party denuclearization talks unable to communicate with North Korea.

Last year, Kono briefly chatted with Ri on the fringes of the ASEAN-related meetings in Manila. It marked the first meeting between the two countries’ top diplomats since August 2015, when then-Foreign Minister Fumio Kishida and then-North Korean Foreign Minister Ri Su Yong met on the sidelines of a regional security forum in Kuala Lumpur.

Kono said he asked Ri to resolve such issues as his country’s nuclear and ballistic missile programs and the abductions but declined to comment on how his counterpart responded.

On Wednesday night, Kono arrived in Singapore. Ri reached the city-state on Friday, flying in from Beijing. Japan and North Korea have no diplomatic ties.