Defense Secretary James Mattis had a packed first full day at work.
By 11:30 a.m., he had received a daily intelligence briefing and spoken with his Canadian counterpart, Minister of National Defense Harjit Sajjan.
He was later scheduled to meet with the members of the Joint Chiefs of Staff in "the Tank," a secure conference room reserved for Joint Chief meetings.
"Secretary Mattis has hit the ground running and focused on establishing a battle rhythm in the building," said Pentagon spokesman Navy Capt. Jeff Davis.
Davis said Mattis is also making a "number of calls" to his foreign counterparts, but did not specify who.
Mattis also brought with him on Monday his new chief of staff, retired Navy Adm. Kevin Sweeney.
Davis also announced Navy Rear Adm. Craig Faller as Mattis's senior military assistant. Faller most recently served as chief of Navy Legislative Affairs.
Mattis's first official day was Saturday, after being sworn in on Friday.
Davis said he spent about four hours at the Pentagon, meeting with Chairman of the Joint Chiefs Marine Gen. Joseph Dunford, Vice Chief Air Force Gen. Paul Selva and Deputy Defense Secretary Bob Work.
Davis said he also used that time to complete his initial in-briefs for ethics and security and to take an entry urinalysis "like everyone else in the Department of Defense does." Mattis also received an initial intelligence briefing and met with his personal staff, he said.
"There will be multiple new staff assignments in the days and weeks ahead," Davis said.