On his first visit to Britain as Pentagon chief, Mattis also took rhetorical jabs at Russia and said America's priority in Syria is defeating the Islamic State group rather than bringing down President Bashar Assad.
At a joint news conference with his British counterpart, Michael Fallon, Mattis was reminded by a reporter that as commander of U.S. forces in the Middle East several years ago, he considered Iran to be the biggest threat to U.S. interests. Asked how he would deal with Iran as secretary of defense, Mattis called Tehran a problem but quickly pivoted to condemning North Korea and described the isolated, communist country as the more immediate threat.
"This is a threat of both rhetoric and growing capability," Mattis said, alluding to the North's recent progress in building nuclear bombs and developing an intercontinental ballistic missile to deliver such weapons to U.S. soil. Experts believe North Korea will develop such capability in the next years, despite an array of international sanctions on the country. The Trump administration has been conducting a broad policy review of North Korea that includes military options, but Mattis stressed other approaches.
"We are working diplomatically, including with those that we might be able to enlist in this effort to get North Korea under control," he said. "But right now it appears to be going in a very reckless manner."