(File photo: Xinhua/Reuters)

US President George W. Bush has asked Secretary of Defense Donald Rumsfeld to remain at the Pentagon and Rumsfeld has agreed, a senior administration official said Friday.

Bush asked Rumsfeld to stay during a weekly meeting on Monday because the nation is at war and he is the best person for the job,the official said. "Secretary Rumsfeld is a proven leader during challenging times," the official said.

Rumsfeld has refused to talk about his future after the re-election of Bush, but said he remained committed to overseeing theIraq war and transforming the military to face the new kind of threat the United States faces.

Rumsfeld, 72, has seen his tenure marked by the push for a missile defense system, transforming the US military into a lighter but more lethal force, and the wars in Afghanistan and Iraq,

He adopted in the Iraq war his military strategy of using fewerbut more flexible troops and relying on technology and integrated combat network. But he was wildly criticized for underestimating the chaotic situation in Iraq after major combatting battles endedand the strengths of the anti-American forces there.

After the Abu Ghraib prisoner abuse scandal became public, Rumsfeld was blamed for failing to respond quickly to internal investigations over the abuse issue. Some called for his resignation, but Bush offered public support for him.

Earlier in the day, Health and Human Services Secretary Tommy Thompson resigned, becoming the eighth member of Bush's 15-member Cabinet to step down.

Bush also nominated Bernard Kerik, the former New York City police commissioner, to lead the Department of Homeland Security, replacing Tom Ridge, the nation's first homeland security secretary who announced his resignation Tuesday.