Top U.S. military officer Gen. Mark Milley said Tuesday that South Korea's decision to scrap an intelligence-sharing pact with Japan is on the agenda for talks he is holding with both nations.

"It'll be a point in discussion there (in South Korea). So we want to try to resolve that issue before it expires," Milley told reporters after meeting with Prime Minister Shinzo Abe. Milley will visit South Korea on Wednesday.

Milley, who became the chairman of the U.S. Joint Chiefs of Staff in October, said he and Abe discussed "a little bit" the issue of the General Security of Military Information Agreement (GSOMIA), which is set to expire on Nov. 23.

The United States has called on South Korea to revisit its decision despite Seoul and Tokyo remaining at odds over wartime compensation and trade issues.

Asked if he is optimistic, Milley said, "We'll find out, we'll see."

The intelligence-sharing pact is seen as important as it allows the U.S. allies to deal with common security challenges, particularly North Korea's repeated test-launches of ballistic missiles.

Washington has been concerned that the worsening relationship between Tokyo and Seoul will hurt trilateral cooperation.

Milley called North Korea's recent firings of missiles a "deep concern," adding that Abe also expressed such a view during their meeting.

North Korea has fired a spate of short-range ballistic missiles, but U.S. President Donald Trump has downplayed the significance of the launches while attempting to engage the North's leader, Kim Jong Un, in dialogue.

In early October, Pyongyang test-fired what it called a new type of submarine-launched ballistic missile into Japan's exclusive economic zone in the Sea of Japan, drawing protest from Tokyo.

"We'd like to enhance our response capabilities and boost deterrence," Abe told Milley at the outset of the meeting.