(AP) - President-elect Barack Obama picked former campaign rival HillaryRodham Clinton as secretary of state Monday. He also announced that Robert Gates would remain as defense secretary, making President Bush's Pentagon chief his own as he seeks to wind down the U.S. role in Iraq.

At a news conference, Obama also introduced retired Marine Gen.James Jones as White House national security adviser, formerJustice Department official Eric Holder as attorney general andArizona Gov. Janet Napolitano as secretary of homeland security.

The announcements rounded out the top tier of the team that willadvise the incoming chief executive on foreign and nationalsecurity issues in an era marked by wars in Iraq and Afghanistanand terrorism around the globe.

"The time has come for a new beginning, a new dawn of Americanleadership to overcome the challenges of the 21st century," Obamasaid as his Cabinet picks stood behind him on a flag-draped stage.

"We will strengthen our capacity to defeat our enemies andsupport our friends. We will renew old alliances and forge new andenduring partnerships."

Obama also appointed campaign foreign policy aide Susan Rice as hisambassador to the United Nations. Obama said he would make her amember of the Cabinet, an increase in stature from the Bush era.

Obama said his appointees "share my pragmatism about the use ofpower, and my sense of purpose about America's role as a leader inthe world."

Watch Sen. Clinton's comments

To view the entire press conference, go to Channel 612 on your iO Digital Cable Box and select iO Extra.