U.S. Defense Secretary James Mattis and Britain's Defence Secretary Michael Fallon pose for a handshake in front of a ceremonial guard of the Household Cavalry Mounted Regiment, as Mattis arrives for their meeting at the Ministry of Defence in London, March 31, 2017. REUTERS/Matt Dunham/Pool

LONDON (Reuters) - U.S. Defense Secretary Jim Mattis said North Korea is acting in a reckless manner and must be stopped.

“This is a threat of both rhetoric and growing capability, and we will be working with the international community to address this, we are doing so right now,” Mattis said in reply to a question about the potential threat to the United States from ballistic missiles.

“Right now it appears to be going in a very reckless manner in what its conduct is portraying for the future and that’s got to be stopped,” Mattis said.