A second senior official has exited the Pentagon leaving policy for the defence department overseen by a retired brigadier general who once called Barack Obama a “terrorist leader”.

The Pentagon’s acting policy chief James Anderson became the second high-level departure this week after the secretary of defence Mark Esper was fired by Donald Trump on Monday.

Stepping into the role vacated by Mr Anderson is Anthony Tata, whose nomination for the same Pentagon job fell apart over the summer when his tweets about the former president and Islamophobic posts came to light.

A defence official confirmed to Politico that Mr Tata is now running the organisation. 

Acting Defence Secretary Christopher Miller, who took over the department on Monday, wrote in a memo: “Effective immediately, and while the position of the Deputy Under Secretary of Defense for Policy is vacant and there is no Acting Deputy Under Secretary of Defense for Policy, Mr Anthony Tata, Senior Advisor to the Secretary of Defense, is delegated the authority of the Under Secretary of Defense for Policy and is directed to perform the duties of the Undersecretary of Defense for Policy.” 

It was expected that Mr Anderson, a Bush administration appointee, would be asked to resign by the White House after the election, following disagreements with the personnel office and for pushing back on the withdrawal from Afghanistan. 

It was thought that he could be the first of several departures following Mr Esper’s termination, and later on Tuesday two more were confirmed. 

Chief of staff Jen Stewart will be replaced by Kash Patel, a former staffer for congressman Devin Nunes, a Trump loyalist. Vice Admiral Joseph Kernan, a retired Navy SEAL who was Undersecretary of Defense for Intelligence has also left, according to reporting by Fox News.

Mr Anderson wrote in his resignation letter that he was grateful to have been entrusted with leading Policy and the key role it plays in the nation’s security.

“Now, as ever, our long-term success depends on adhering to the US Constitution all public servants swear to support and defend."

After Mr Tata’s nomination for the role was withdrawn in July he was designated as the official performing the duties of the deputy undersecretary of defence for policy, reporting to Mr Anderson.

In addition to tweets about former president Obama, CNN also uncovered posts in which Mr Tata called Islam the “most oppressive violent religion I know of” and hit out at Democrat politicians.

Other tweets singled out former CIA direct John Brennan. One said: "might be a good time to pick your poison: firing squad, public hanging, life sentence as prison b*tch, or just suck on your pistol. Your call. #Treason #Sedition #crossfirehurricane #Obamagate.”

Senators on the committee charged with overseeing Mr Tata’s nomination reacted with horror, calling him “by far the Trump’s most unqualified and ill-suited senior defence nominee — a high bar.”

Mr Tata was placed into a new role with similar duties instead.

Now vice president-elect, then Senator, Kamala Harris said at the time: “Anthony Tata has no business working in the Pentagon in any capacity. His vile Islamophobic comments are disqualifying, period. Our service members deserve better from their leadership.”