Mr Trump continually boasted about Wall Street's steep climb during the first year of his presidency, but has sought to deflect blame since markets hit a rough patch in 2018.

On Sunday US Treasury Secretary Steven Mnuchin took the unusual step of calling the chief executives of America's six largest banks in a bid to soothe market jitters.

On Monday, he called top market regulators and officials from the US central bank to allay fears about the economy.

Mr Mnuchin hosted the call with the President's Working Group on Financial Markets to "discuss co-ordination efforts to assure normal market operations", according a treasury statement.

The board of governors of the US Federal Reserve System, the Securities and Exchange Commission and the Commodities Futures Trading Commission are on the working group.

• US shutdown could stretch into new year

Not a very merry Christmas

Analysis by Samira Hussain, business reporter, BBC News, New York

It is rare for a US treasury secretary to make public his discussions with American financial institutions. But that is exactly what Mr Mnuchin did.

He was attempting to ease financial markets but Monday's swoon showed he did the opposite.

So then President Trump weighed in by tweet and renewed his criticism of the Federal Reserve. That also did not have the desired effect. Instead of the typical Santa Rally, we saw US investors flee stocks for safety.

Not exactly the Christmas cheer the White House was hoping for.

What does this mean for 2019? A lot will depend on what happens in Washington: government shutdown, simmering trade tensions and the president's tweets.

One thing has been made very clear: if the White House wants to calm nervous investors, it's going to need to get much better at its messaging.