It wasn’t even midday, Eastern Standard Time, on Christmas Eve and US President Donald Trump had already fired off more than half a dozen tweets taking aim at his political foes and obsessions.

According to Mr Trump, the Federal Reserve is the “only problem our economy has”— a tweet which may have been in response to a savage article than ran in the New York Times over the weekend listing the myriad problems Mr Trump’s administration now faces, including a possibly fragile economy.

The Federal Reserve has raised its key short-term rate four times this year given the low unemployment rate and brisk pace of economic growth.

Mr Trump has argued that the Fed is hindering the economy through its rate increases, which are intended to prevent inflation from rising too high.

His major target for criticism has been Jerome Powell, whom the US President elevated to chairman early this year.

In other Christmas Eve morning tweets Mr Trump also pointed the finger at the senators who believe he is isolationist in his international policies.

But Mr Trump reserved special criticism for Bob Corker, the current chairman of the Senate’s Committee on Foreign Relations, who had dared to criticise Mr Trump over the government shutdown.

Mr Trump’s sniping at Mr Corker, a Republican, demonstrates that no one is beyond Mr Trump’s ire, not even members of his own party.

As Mr Trump claimed in accepting the Republican presidential nomination in 2016, “I alone can fix it” — referring to America’s economic and political system.

Mr Trump seems convinced that the has done so, tweeting:

It comes as the US has been sharply criticised for pulling its troops from Syria and Afghanistan, with Mr Trump claiming that Turkey can fight what is left of the war against ISIS.

Mr Trump also brought up the topic of the border wall, attacking the Democrats who he accused of being two-faced about the border wall and tweeting that the issue is more complex than his critics realise:

The media was again accused by Mr Trump of inaccurate reporting, including misrepresenting his view of the Acting Attorney-General, Matthew Whitaker:

One Twitter follower responded to Mr Trump, tweeting his reply:

“Mr. President, it’s Christmas Eve. Don’t you have some good works, soup kitchen volunteering, school repainting, Santa impersonating, calls to the troops, or other acts of charity to perform?

“Oh, I forgot. Wrong president.”

On Monday afternoon the Dow plunged more than 650 points as Mr Trump hammered the Federal Reserve Bank.

According to ABC News it marks the worst December since the Great Depression.

The sooner-than-expected departure of US Defense Secretary Jim Mattis has shifted the focus to Mr Trump’s appointment of an acting Pentagon chief and plans for a permanent replacement.

It also signals an acrimonious end to a tense relationship between Mr Trump and Mr Mattis that had eroded in recent months.

A fracture developed last week over Mr Trump’s decision to withdraw US troops from Syria and worsened after Mr Mattis’ public disagreement with Mr Trump, aired in his resignation letter.

Deputy Defence Secretary Patrick Shanahan will take over as acting secretary on Jan. 1, Mr Trump announced in a tweet Sunday.

He had worked for more than three decades at Boeing Co. and was a senior vice president when he became Pentagon deputy in July 2017.

In the new year Mr Trump wants to focus on streamlining purchases at the Pentagon, an issue on which Mr Shanahan has already been working, a White House official said.

In a March 2016 report, the Puget Sound Business Journal called Mr Shanahan a Boeing “fix-it” man who was central to getting the 787 Dreamliner on track after production problems in the program’s early years.

An acting Defence Secretary is highly unusual. Historically when a secretary has resigned, he has stayed on until a successor is confirmed.

Mr Mattis, a retired Marine Corps general, had been expected to retain his position through February.