By Barbara Starr

President Barack Obama made the rare move of calling the secretary of the Army on Tuesday night to express concern about reports of abuse at an Army child care facility, U.S. officials told CNN.

"The president made clear that we must have a zero-tolerance policy when it comes to protecting the children of service members from abuse. The president urged Secretary (John) McHugh to conduct the investigation into its hiring practices at (Army day care facilities)," a White House official told CNN's Lesa Jansen.

It is highly unusual for the president to call a military service secretary regarding a criminal matter, said a senior U.S. defense official who has served at the Pentagon for more than a decade.

The Department of Defense is now reviewing the hiring procedures at military day care centers and other youth facilities after the September arrests of two workers at Fort Myer in Virginia. The workers were charged Tuesday with "assault on a child under the age of 16" in connection with incidents that occurred in September.

After the arrests, the Army looked at the workers' backgrounds and realized that they were questionable and that the workers should not have been hired, according to a defense official.

While the problem had been known for some time, the situation was not brought to Pentagon leadership, including Secretary of Defense Leon Panetta, until Tuesday night, U.S. officials said.

The Army began looking at all 130 day care workers at Fort Myer. Not all were directly involved in child care. The review found that 30 employees had questionable backgrounds, including records of sexual abuse of a minor, sexual assault and assault, although some of the charges had been dropped, according to one official. There were also some minor offenses. None was on the national registry of sex offenders.

However, another senior Department of Defense official told CNN that such charges would have disqualified the staffers from working in a day care facility with children.

The 30 employees were removed Friday out of "an abundance of caution," according to Col. Fern Sumpter, garrison commander at Fort Myer.

McHugh first learned the extent of the problem Friday. The same day, parents were notified that the center was closing due to a lack of staff, though officials could not say whether the parents were told the reason. The Department of Defense sent inspection teams Monday, but McHugh did not inform Panetta of the problems until Tuesday.

Panetta met with Obama Tuesday afternoon, according to the White House schedule. On the same day, the defense secretary ordered a review of hiring procedures at all of the military's child development centers.

"As a department, protecting our service members and their families is paramount. That includes doing everything we can to provide for the safety of children attending (child development centers) throughout the department and ensuring they are provided with the highest quality care by dedicated professionals," Panetta said in a statement.