MINOT (AP) - Defense Secretary Robert Gates, hours after being named President-elect Barack Obama's choice to stay on the job, told Air Force membes at the Minot Air Force Base that last year's lapses in nuclear weapons procedures were unacceptable and the department is doing a "top to bottom'" review of its nuclear stewardship.

Hundreds of airmen packed into a B-52 hangar at the base today to listen to Gates, who thanked them and told them their mission is vital.

The Minot base drew attention last year when nuclear cruise missiles were mistakenly loaded onto a B-52 bomber and flown to Louisiana. The incident was cited by Gates as one factor leading to the ouster of Air Force Chief of Staff Gen. Michael Moseley and Air Force Secretary Michael Wynne.

Gates said today the missteps stemmed from a "long-standing slide of nuclear stewardship" that did not get the attention, personnel or funding it deserved.

"You must never take your duties lightly," he told the airmen. "There is simply no room for error." Gates came to Minot from Chicago, where Obama announced he had asked the 65-year-old Pentagon chief to stay on the job. Gates said it was not his "expectation or desire," but said he was persuaded to "serve a little while longer."

He said he feels honored to serve under Obama, who will be the eighth president he has served.