A day after North Korea's leader called President Donald Trump "deranged" and "a rogue and a gangster," Trump fired back, tweeting Friday morning that Kim Jon Un "is obviously a madman."
Trump continued his lashes at Kim at a campaign rally for Alabama Sen. Luther Strange saying "We can't have madmen out there shooting rockets all over the place."
He also said "Rocket Man should have been handled a long time ago" by previous presidents.
It's the latest escalation in a suddenly personal war of words between the two leaders that's stretched back weeks, unfolding as North Korea has showcased an enhanced nuclear missile capability. In their statements, Trump and Kim combined insults with threats.
"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!" Trump tweeted.
On Thursday, Kim said Trump is "unfit to hold the prerogative of supreme command of a country" who will "pay dearly" for threats he's made. Trump said on the floor of the United Nations General Assembly that the United States would "totally destroy" North Korea if "forced to defend itself or its allies."
Later, South Korean media reported North Korea's top diplomat says his country may test a hydrogen bomb in the Pacific Ocean to fulfill leader Kim Jong Un's vow to take the "highest-level" action against the United States.
Kim's statement was a unique escalation itself, marking the first time Kim or his predecessors had addressed the world directly, according to Seoul's Unification Ministry, which is responsible for North-South relations.
The latest insults between Trump and Kim come as Trump expands the Treasury Department's ability to target anyone conducting significant trade in goods, services or technology with North Korea and to ban them from the U.S. financial system.
It imposes a 180-day ban on vessels and aircraft that have visited North Korea from visiting the United States.
Trump also praised China on Thursday for what he said was instructions to its banks to cut off business with North Korea. He said the action "was a somewhat unexpected move and we appreciate it."
But China is disputing that. A foreign ministry spokesman said Friday that is Trump's assertion is "not consistent with the facts," giving no indication what steps China might be taking.
The spokesman, Lu Kang, said Beijing complies with U.N. Security Council resolutions. The council has told member countries to ban most activity abroad by North Korea's banks in response to its nuclear and missile tests.
Asked at a regular briefing about Trump's comment, Lu said, "As far as I know, what you have mentioned just now is not consistent with the facts."
Lu gave no explanation but added, "in principle, China has always implemented the U.N. Security Council's resolutions in their entirety and fulfilled our due responsibility."
China wants to stop North Korea's nuclear and missile development but has warned against pushing the government of Kim Jong Un so hard it collapses or hurting ordinary North Koreans.
Treasury Secretary Steve Mnuchin said he spoke at length with the head of China's central bank but "I am not going to comment on confidential discussions."
The Chinese central bank would not take questions by phone and did not immediately respond to a faxed request for comment.