U.S. Senator Cory Gardner has told Radio Free Asia that if North Korea demonstrates concrete progress in denuclearization, a suspension in South Korea-U.S. military exercises could be negotiated by military commanders.

The remark was in response to North Korean leader Kim Jong-un's call for a halt to South Korea-U.S. joint drills and a ban on deploying U.S. strategic assets and war apparatus on the Korean Peninsula.

The Colorado Republican who chairs the Senate Foreign Relations Subcommittee on East Asia, the Pacific, and International Cybersecurity made it clear that North Korea taking concrete measures toward denuclearization is a precondition to a suspension in joint exercises.

Gardner also said that military commanders must also agree with the fact that a suspension will not affect the defense readiness posture.

He said the U.S. is concerned about not only South Korea but also about North Korea attacks on other U.S. allies in the region, including Japan.