The nominee for U.S. deputy defense secretary says North Korea’s missiles and weapons of mass destruction pose a direct and serious threat to U.S. allies and partners.

Ashton Carter made the remark Tuesday in a written reply to advance policy questions by the Senate Armed Services Committee ahead of his confirmation hearing.

Carter said the North’s missile and WMD programs also “have the potential to become a direct threat to U.S. territory.”

He then stressed that the U.S. must “continue to carefully monitor North Korea’s WMD and missile development programs and related proliferation activities.”

Carter said the North’s sinking of the Cheonan naval ship and shelling of Yeonpyeong Island last year “provide a sober reminder that Pyongyang is willing to utilize its capabilities to undertake provocative actions.”