WASHINGTON — Up to 10,000 U.S. troops will be off Haiti's shores by Monday to help distribute aid and prevent potential rioting among desperate earthquake survivors, the top U.S. military officer said today.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, also said the total American presence in and around the beleaguered country could rise beyond 10,000 as U.S. military officers determine how much assistance may be needed in the days ahead.

His assessment came as the State Department updated the toll of U.S. dead from Tuesday's 7.0 magnitude quake to six and cautioned that the casualty count is likely to rise still further.

State Department spokesman P.J. Crowley said that in addition to the previously reported death of agency employee Victoria DeLong, there have been at least five other confirmed U.S. deaths — all private U.S. citizens whose names have not been released publicly.

President Obama has planned a public statement on the situation from the White House at 1 p.m.