US President Donald Trump was convening his national security team Sunday to weigh options including drastic economic sanctions against North Korea after Pyongyang detonated what it claimed was a hydrogen bomb able to fit atop a missile.

The US president said in a tweet that the time for “appeasement” was over, and a top adviser said Trump was weighing “all our options.”

“The national security team is monitoring this closely,” said White House press secretary Sarah Huckabee Sanders, in announcing the urgent meeting on a US holiday weekend.

In a Twitter message, Trump denounced the unexpectedly powerful test – said to be the North’s first blast to exceed in magnitude the atomic bombing of Hiroshima, Japan – as “very hostile and dangerous to the United States.”

North Korea said its test of what it described as a hydrogen bomb designed for a long-range missile was “a perfect success.”

The Sunday blast was so powerful that US monitors measured a 6.3-magnitude earthquake near the North’s main testing site, and it was felt in China and Russia.

Pyongyang residents threw their arms aloft in triumph as a jubilant television newsreader hailed the “unprecedentedly large” blast; she said it had moved the country closer to “the final goal of completing the state nuclear force.”

Condemnation from world capitals was swift, including from China and Russia while South Korean President Moon Jae-In called for the “strongest punishment.”