President-Elect Barack Obama announced additional key White House staff on Sunday in the latest round of appointments as the Democrat's transition team works to fill out the senior ranks of his administration.

Pete Rouse will serve as senior adviser to the president, and Mona Sutphen and Jim Messina will both serve as deputy chiefs of staff.

"These individuals are important additions to a team with the experience and ability to help our nation overcome pressing challenges at home and around the world," Obama said in a press release.

Rouse -- Obama's chief of staff while in the U.S. Senate -- has worked for various members of Congress for more than 30 years, including former Democratic leader Tom Daschle, whom he served for 19 years.

As Obama's chief of staff in the Senate, Rouse had a critical role in helping to launch Obama's 2008 presidential run.

Mona Sutphen is a member of Obama's transition team, and has been managing director of Stonebridge International, a strategic consulting firm based in Washington, D.C. Sutphen also was a foreign service officer and worked on the National Security Council in the Clinton White House.

Jim Messina -- Obama's national chief of staff during the presidential campaign -- is currently the director of personnel for Obama's transition team.

The Associated Press contributed to this report.