Washington: The US today cast doubts over North Korea's claims of successfully testing a hydrogen bomb, noting that initial analysis is not consistent with the claims of Pyongyang.

"Initial analysis is not consistent with N Korean claims of a hydrogen bomb explosion," White House Press Secretary, Josh Earnest, told reporters at his daily news conference. Calling North Korea's action "provocative", the White House official reiterated America's "rock-solid commitment to safety and security of South Korea and Japan."

He asked North Korea to end its provocative actions.