WASHINGTON — U.S. Defense Secretary James Mattis warned North Korea in stark terms on Sunday that any attack on the U.S. or its allies would be met with a massive military response, in comments that came after a national-security briefing with President Donald Trump called in response to Pyongyang’s sixth and most powerful nuclear test.

“We have many military options and the president wanted to be briefed on each one of them,” said Mattis in brief comments Sunday afternoon, accompanied by Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff. Mattis warned that any attacks on the U.S., Japan or South Korea “will be met with a massive military response, a response both effective and overwhelming.”