Gen. Mark Milley took the oath of office Monday to become the 20th Chairman of the Joint Chiefs of Staff as he hailed the U.S. Army as the best equipped in the world.

Axar.az reports citing Anadolu Agency.

The ceremony started with prayers and the new military chief took the oath on a Bible during an outdoor ceremony at the White House from his predecessor, Gen. Joseph Dunford, who was named to the post by then-President Barack Obama in 2015.

U.S. President Donald Trump nominated Dunford for a second two-year term in 2017.

Trump, Vice President Mike Pence, and Defense Secretary Mark Esper were present.

Milley vowed to keep the U.S. military a "primary fighting force, respected by our friends and feared by our adversaries.”

"We stand ready to keep the peace or if necessary win a war, we are the best equipped, best trained, best-led military in human history," he said.

Trump, for his part, said Milley will serve him as his top military adviser.

"I have absolute confidence he will fulfill his duty with the same brilliance and fortitude he has shown through his long and distinguished career," said Trump.

Milley had been serving as Chief of Staff of the Army since 2015.

The chairman of the Joint Chiefs of Staff is the nation’s highest-ranking military officer and serves as the principal military advisor to the president, defense secretary and National Security Council.