White House aide Sebastian Gorka warned Tuesday that North Korea should not test President Trump.
"This is a Lilliputian nation, if you compare it to our capabilities," Gorka said on Fox Business.
"So this is bluster. This is nothing else except blackmail, and we do not give in to blackmail, and North Korea and the head of the North Korea Stalinist regime should not test this president."
The United Nations Security Council voted over the weekend to impose new sanctions against North Korea in retaliation for its recent ballistic missile tests.
Following the vote, North Korea vowed to respond, calling the new sanctions a "violent infringement of its sovereignty."
On Tuesday, North Korea warned of "physical action" after the new sanctions.
“Packs of wolves are coming in attack to strangle a nation,” the North Korean statement, carried its state-run Korean Central News, read, according to The New York Times.
“They should be mindful that the D.P.R.K.’s strategic steps accompanied by physical action will be taken mercilessly with the mobilization of all its national strength.”
President Trump on Tuesday called for decisiveness in dealing with the North Korean threat.
"After many years of failure, countries are coming together to finally address the dangers posed by North Korea," he tweeted. "We must be tough & decisive!"