Vedant Patel, principal deputy spokesperson for the Department of State, is seen answering a question in a daily press briefing at the department in Washington in this image captured from the department's website, Oct. 26. Yonhap

A nuclear test by North Korea would constitute a "grave escalatory action" that will be met by serious consequences, a state department spokesperson said Wednesday.

Vedant Patel, principal deputy spokesperson for the department, insisted the U.S. has a "number of tools" to hold North Korea accountable for any future provocations.

"A seventh nuclear test, should it happen, would constitute a grave escalatory action and seriously threaten regional stability, international stability, security in the region, and it would also undermine the global non-proliferation regime and efforts that are being undertaken," he said in a daily press briefing.

Pyongyang conducted its sixth and last nuclear test in September 2017. U.S. officials, including state department press secretary Ned Price, have said the North may conduct its seventh nuclear test "at any time."