U.S. Ambassador to the United Nations Nikki Haley warned North Korea on Friday that she is more than willing to let Defense Secretary Jim Mattis deal with the nuclear threat from Pyongyang if sanctions do not work.

Haley said recent sanctions have “strangled” North Korea’s “economic situation,” calling the impact “dramatic.”

But she said there's only so much the U.N. Security Council can do “when you cut 90 percent of the trade and 30 percent of the oil.”

“So having said that, I have no problem kicking it to General Mattis because I think he has plenty of options,” Haley said at the White House briefing, where she and National Security Adviser H.R. McMaster previewed U.S. efforts at the U.N. General Assembly next week.

North Korea conducted its longest-ever test flight of a ballistic missile Friday, sending an intermediate-range weapon hurtling over U.S. ally Japan into the northern Pacific Ocean in a launch that signals both defiance of its rivals and a big technological advance.

McMaster stressed Friday that the U.S. is still trying to resolve the conflict diplomatically. Joining Haley at the briefing, he said it’s important to employ “rigorous enforcement of those sanctions” in pursuit of that route but acknowledged the United States is willing to use force.

“There is a military option,” he said. “Now, it’s not what we prefer to do. So what we have to do is call on all nations, call on everyone to do everything we can to address this global problem short of war.”

He said “denuclearization” is the only acceptable outcome.

“We’re out of time,” McMaster said. “As Ambassador Haley said before, we’ve been kicking the can down the road and we’re out of road.”

Since President Trump threatened North Korea with "fire and fury" in August, the North has conducted its most powerful nuclear test, threatened to send missiles into the waters around the U.S. Pacific island territory of Guam and launched two missiles of increasing range over Japan.

The Security Council scheduled an emergency closed-door meeting Friday afternoon in New York. On Monday, it unanimously approved its toughest sanctions yet on North Korea over its nuclear test.

The Associated Press contributed to this report.

