Patrick Shanahan has taken over the helm of the Pentagon, as U.S. President Donald Trump attacked his Defense Department predecessor, pointing to what he said was a lack of success in Afghanistan.

Shanahan, who has been serving as deputy defense secretary, worked his first day in office as acting defense secretary on Jan. 2, 2019, as the replacement for Jim Mattis, who resigned as defense chief on Dec. 20, 2018, saying his policies were not fully "aligned" with the president.


Trump has not specified a time frame for choosing a permanent defense secretary or said whether Shanahan could potentially assume that role.

Mattis initially said he would be leaving the Pentagon at the end of February 2019. But Trump later announced that Mattis, 68, would be leaving earlier after the defense secretary published a letter that directly criticized the president.

Former Secretary of Defense Jim Mattis.

(DOD photo by Army Sgt. Amber I. Smith)

In televised remarks on Jan. 2, 2019, Trump said he "essentially fired" Mattis. "I'm not happy with what [he has] done in Afghanistan — and I shouldn't be happy," said Trump, as Shanahan sat by his side.

"I wish him well. I hope he does well. But as you know, President [Barack] Obama fired him, and essentially so did I. I want results."

A former Marine general, Mattis was fired by Obama in 2013 as head of U.S. Central Command over what the then-president said were too hawkish views toward Iran.

Shanahan, 56, meanwhile, said his priorities would include the impending U.S. troop withdrawal from Syria and countering China's military might.

"While we are focused on ongoing operations, Acting Secretary Shanahan told the team to remember: China, China, China," a Pentagon official said.

This article originally appeared on Radio Free Europe/Radio Liberty. Follow @RFERL on Twitter.