President-elect Barack Obama takes questions from reporters during a news conference in Chicago, Monday, December 1, 2008, with, from left to right: Attorney General-designate Eric Holder; Homeland Security Secretary-designate Janet Napolitano; Defense Secretary Robert Gates; Vice President-elect Joe Biden; Secretary of State-designate Sen. Hillary Rodham Clinton, D-N.Y.; National Security Adviser-designate Ret. Marine Gen. James Jones; and United Nations Ambassador-designate Susan Rice. [Xinhua/Reuters]

US President-elect Barack Obama announced on Monday his national security team, including former first lady Hillary Rodham Clinton as secretary of state and incumbent Defense Secretary Robert Gates, who would retain his post.

"America must be strong at home and abroad," Obama told a news conference in his transition office headquarters in Chicago, Illinois, drawing a full stop to a month-long speculations on his cabinet members.

"To succeed, we must pursue a new strategy that power: our military and diplomacy, our intelligence and law enforcement, our economy and the power of our moral example," said the president-elect with all national security team members announced standing beside him.

"They share my pragmatism about the use of power, and my sense of purpose about America's role as a leader in the world," he said.

US Democratic presidential nominee Barack Obama (R) and Senator Hillary Rodham Clinton attend a money raising meeting in New York, the United States, in this file photo taken on July 10, 2008. US President-elect Barack Obama nominated Senator Hillary Rodham Clinton for Secretary of State at a news conference in Chicago on Monday. [Hou Jun/Xinhua]

Obama referred his former presidential rival Clinton as "a friend, a colleague, a source of counsel and as a campaign opponent" who possesses "an extraordinary intelligence and toughness".

Clinton's appointment to the top diplomatic official, as Obama said, is "a sign to friend and foe of the seriousness of my commitment to renew American diplomacy and restore our alliance."

Echoing Obama's remarks, Clinton told the press conference that she would make the United States a new force for positive change and work with the global community to solve crises around the world.