The Seleka coalition took control over Bangui in what's described by the U.S. State Department as an illegitimate seizure of power. The alliance said it embraced a power-sharing deal reached in Gabon early this year but later suspended the Constitution and Parliament.
State Department spokesman Patrick Ventrell said the U.S. government had reports of extensive looting and a "trail of destruction" left by rebel forces in CAR.
"We strongly condemn the illegitimate seizure of power by the Seleka rebel alliance, the ouster of President (Francois) Bozize, (rebel leader) Michel Djotodia's self-appointment as president and the announcement of the suspension of the CAR constitution and Parliament," he said.
The U.N. Security Council late Tuesday condemned rebel activity, saying there were accounts of child soldiers, sexual violence and other abuses coming out of CAR.
Bozize fled to Cameroon. Ventrell said rebel forces occupying Bangui need to step aside to let Prime Minister Nicolas Tiangaye and his government lead the country.
"They're the ones that should be in charge and actually governing the country," he said.