As Chinese leader Xi Jinping makes a plea for restraint, U.S. ambassador to the United Nations Nikki Haley suggested the United States would not rule out using use military force to respond to additional missile testing by North Korea.

The U.N. Security Council last week condemned the actions by North Korea as “highly destabilizing behavior.”

Haley’s comments to NBC‘s “Today” show come a day after the U.S. Navy strike group led by nuclear aircraft USS Vinson began carrying out exercises with Japanese warships near the Philippines. They also follow, as CNN wrote, “North Korea’s state-run newspaper Rodong Sinmun [saying] in an editorial the country is ready to illustrate its ‘military force’ by sinking a ‘nuclear-powered aircraft carrier with a single strike’.”

North Korean leader “Kim Jong-un is starting to flex his muscles because he feels the pressure” and is “starting to get paranoid,” Haley said, referring to the Security Council’s condemnation and the fact that “China has been considerably helping in putting pressure on him.”

Her country’s perspective, Haley said, is that “the United States is not looking for a fight, so don’t give us a reason to have one.”

Asked by co-anchor Savannah Clark Guthrie if “a preemptive strike against North Korea is really being considered,” Haley replied:  “We are not going to do anything unless he gives us reason to do something.” Pressed by Guthrie as to what that reason would be, Haley said, “If you see him attack a military base, if you see him if you see some sort of intercontinental ballistic missile, then obviously we’re going to do that. Now, we’re saying don’t test, don’t use nuclear missiles, don’t try and do any more actions. And I think he’s understanding that.”

“If he tests another intercontinental ballistic missile, if he were to test another nuclear device, when you say, ‘Obviously we’re going to do that,’ do you mean military retaliation?” anchor Matt Lauer asked.

“I think then the president steps in and decides what’s going to happen,” Haley said.