A senior U.S. official said on Tuesday that the United States is expending "enormous effort" to increase trilateral security cooperation with South Korea and Japan. 

U.S. Assistant Secretary of State for East Asian and Pacific Affairs David Stilwell made the remarks in a prepared statement for the House Foreign Affairs Subcommittee on Asia ahead of his scheduled testimony Wednesday.

According to the subcommittee, Stilwell also said that the U.S. is ready to resume denuclearization talks with North Korea, but will maintain sanctions on the regime for now. 

The top official said that eliminating the threat to the U.S. and its allies posed by North Korea's illicit nuclear and ballistic missile programs is a top diplomatic priority. He added that the final, fully verified denuclearization of North Korea has been a top diplomatic priority since the beginning of the Trump administration. 

He also said that the U.S. coordinates closely with its allies and partners in the region and around the world, particularly South Korea and Japan, to maintain international unity and ensure continued implementation of existing sanctions.