U.S. Defense Secretary Lloyd Austin said on Tuesday that the United States will continue to strengthen security on the Korean Peninsula through bilateral and trilateral cooperation despite North Korea's provocations.

The U.S. defense chief made the remarks in a statement submitted to a hearing of the Senate Armed Services Committee on a defense budget request.

Austin said that the U.S. remains vigilant against persistent and evolving threats from North Korea, Iran and international terrorists.

The defense secretary added that the U.S. remains steadfast and ironclad in its extended deterrence commitments to South Korea and Japan, and continues to demonstrate its ability to respond rapidly and firmly to any North Korean provocation.

He also said that the U.S. is working to strengthen and modernize its alliances with South Korea and Japan while continuing to ensure that the U.S. forces in and around the Korean Peninsula are ready to "Fight Tonight" in the event of aggression by North Korea, quoting a motto of the Eighth Army stationed in South Korea.