New Interior Department Secretary Ken Salazar was greeted by horse-mounted police and a lobby full of his staff Wednesday, and he unveiled longtime friend Tom Strickland as his top aide.

In brief remarks, Salazar promised the staff they all would be part of the change that President Barack Obama is bringing to the country and to Washington.

"We, together, all of us in this department and all of its agencies and all of its bureaus, are going to be part of changing the world for the better," Salazar said from under his trademark cowboy hat.

He said he was honored and humbled by the greeting.

He alluded to his marching orders from Obama, which include a mandate to clean up the department after a series of scandals during the previous administration of President George W. Bush.

"There are a few problems here and there," Salazar said. "We are going to root those problems out, OK?"

Strickland brings a prosecutor's experience to the chief of staff's job .

In 1999, then-President Bill Clinton tapped Strickland for United States attorney for the region that includes Denver. He was the top federal prosecutor while Salazar was Colorado's attorney general.

Strickland, who twice lost Senate races to Wayne Allard, left a job in the health care industry.

"These are issues I know and love, and it's a chance to do it at a time of historic opportunity," Strickland said.