Photo: The Canadian Press

President Donald Trump has added economic sanctions to his fiery military threats against North Korea, and renewed his rhetorical offensive against Kim Jong Un on Friday, calling the reclusive leader "obviously a madman."

Trump's move to punish foreign companies that deal with the North was the latest salvo in a U.S.-led campaign to isolate and impoverish Kim's government until his country halts its missile and nuclear tests. Trump announced the measures Thursday as he met leaders from South Korea and Japan, the nations most immediately imperiled by North Korea's threats of a military strike.

"North Korea's nuclear weapons and missile development is a grave threat to peace and security in our world and it is unacceptable that others financially support this criminal, rogue regime," Trump said as he joined Japanese Prime Minister Shinzo Abe and South Korean President Moon Jae-in for lunch. "Tolerance for this disgraceful practice must end now."

The volley of insults continued Friday, as Trump sent out a predawn Twitter post berating Kim.

"Kim Jong Un of North Korea, who is obviously a madman who doesn't mind starving or killing his people, will be tested like never before!" the president tweeted.

Trump's executive order expanded the Treasury Department's ability to target anyone conducting significant trade in goods, services or technology with North Korea, and to ban them from interacting with the U.S. financial system.

"Foreign financial institutions must choose between doing business with the United States or facilitating trade with North Korea or its designated supporters," the order says. It also issues a 180-day ban on vessels and aircraft that have visited North Korea from visiting the United States.