WASHINGTON • The United States has slapped unprecedented sanctions on a Chinese bank accused of laundering North Korean cash after President Donald Trump said Beijing's efforts to put the brakes on Pyongyang's nuclear drive had failed.

As South Korea's new president visited Washington, the Treasury Department announced the Bank of Dandong would be severed from the US financial system for acting "as a conduit for illicit North Korean financial activity".

And while Treasury Secretary Steven Mnuchin said the move was not targeted at China's government, it is likely to infuriate Beijing, which says it has been unstinting in its efforts to ease tensions with North Korea.

The announcement came on the same day that it emerged the Trump administration had approved US$1.3 billion (S$1.8 billion) in arms sales to Beijing's archrival Taiwan and as the State Department voiced concerns about basic freedoms in Hong Kong under Chinese rule.

Mr Trump has pushed China to do more to rein in the North Korean regime and its leader Kim Jong Un. However, he raised eyebrows last week when he thanked his Chinese counterpart Xi Jinping for Beijing's help but then concluded that Mr Xi's efforts had "not worked out".

The Treasury announcement said Dandong had been identified as "a foreign bank of primary money- laundering concern" that had been "facilitating millions of dollars of transactions" for companies involved in North Korea's weapons of mass destruction and ballistic missile programmes.

The bank will now be prevented from having accounts or doing business with US financial institutions.

The department also sanctioned two Chinese individuals said to have established front companies to facilitate financial transactions for North Korea, and a Chinese shipping company accused of helping smuggle banned luxury goods into the country.

AGENCE FRANCE-PRESSE