The United States blacklisted a small Chinese bank accused of illicit dealings with North Korea on Thursday, escalating the pressure on Beijing to rein in its wayward ally amid increased signs of frustration among President Donald Trump and his top advisers with China's diplomatic efforts.

The Treasury Department declared the Bank of Dandong a "primary money-laundering concern," proposing to sever it entirely from the US financial system, pending a 60-day review period.

Although Mr Trump's treasury secretary said the move didn't target China, it comes a week after the president lamented that China's promise to help with North Korea "has not worked out."

Mr Trump had been leaning on President Xi Jinping to help stop the North's development of nuclear weapons before they can threaten the US homeland. A main focus of the coordination has been getting China to fully enforce international sanctions intended to starve North Korea of revenue for its nuclear and missile programs.