Tokyo will dispatch a senior diplomat to Singapore to collect information on the planned summit next month between the United States and North Korea, Japanese government sources said.

Japan aims to use the momentum generated by their improving ties to help resolve the long-standing abduction issue.

The vexing issue involving Japanese kidnapped by Pyongyang in the 1970s and 1980s has prevented the two countries from formally establishing diplomatic ties.

Kenji Kanasugi, director-general of the Foreign Ministry's Asian and Oceanian Affairs Bureau, will head the liaison team for the June 12 summit between U.S. President Donald Trump and North Korean Leader Kim Jong Un. He will be accompanied by Masaaki Kanai, director of the bureau's Northeast Asia Division.

Although North Korea threatened last week to cancel if the United States continues to pressure it to unilaterally relinquish its nuclear weapons, Japan believes the summit is likely to be held.

"It will be a historic meeting between a North Korean leader and a U.S. president," one of the sources said. "I don't believe Mr. Kim would easily blow such an opportunity."

The liaison team is expected to seek contact with officials from both countries while in Singapore. Kanasugi is charged with overseeing the negotiations with North Korea.

There is speculation Prime Minister Shinzo Abe or Foreign Minister Taro Kono may visit Singapore to be briefed by Trump on the summit. But the government is apparently taking a wait-and-see approach toward North Korea before making its decision.

Kanasugi, who will visit Singapore from June 11 to 13, is expected to work closely with U.S. officials ahead of the event and to be briefed by them afterward. Kanai, director of the bureau's Northeast Asia Division, plans to accompany him, the sources said.