U.S. Defense Secretary James Mattis on Sunday warned North Korea that it would be met with a "massive military response" if it threatened the U.S. or its allies, The Hill reports.

"Any threat to the United States or its territories including Guam or our allies will be met with a massive military response," Mattis said in a statement outside of the White House after meeting President Donald Trump.

"Kim Jong Un should take heed the United Nations Security Council's unified voice. All members unanimously agreed on the threat North Korea poses. And they remain unanimous in their commitment to the denuclearization of the Korean peninsula. Because we are not looking to the total annihilation of a country, namely, North Korea," he continued, referring to the North Korean dictator.

Mattis said the U.S. had "many military options" regarding the Korean peninsula, and that the president wanted to be briefed on all of them.

The statement came hours after North Korea successfully tested a hydrogen bomb (H-bomb), causing a 6.3-magnitude earthquake in the country.

The test came after North Korean media claimed the country had developed an H-bomb which can be loaded into the country's new intercontinental ballistic missile (ICBM).

Earlier on Sunday, Trump addressed the latest North Korean test and, when asked whether he would launch a military strike on North Korea, he replied, “We’ll see.”

Last week, Trump said that talking with North Korea was no longer the answer, after the country launched an ICBM over Japanese airspace.

Mattis had indicated last week that the U.S. preferred to solve the crisis with North Korea in a diplomatic manner.