The United States slammed North Korea's rocket launch Wednesday as "a highly provocative act" and indicated it would seek tougher sanctions on Pyongyang, saying it will work with U.N. Security Council members to pursue "appropriate action."

"North Korea's launch today — using ballistic missile technology despite express prohibitions by U.N. Security Council resolutions — is a highly provocative act that threatens regional security," Tommy Vietor, spokesman of the National Security Council, said in a statement Tuesday Washington time.

Vietor said the United States will "work with its six-party partners, the U.N. Security Council and other U.N. member states to pursue appropriate action" against North Korea.