A senior administration official tells The Associated Press that President Barack Obama is demanding that Syrian President Bashar Assad resign for unleashing a sustained assault against his people.
The official says Obama will make his first explicit call for the Syrian leader to leave power in a written statement Thursday. Secretary of State Hillary Rodham Clinton then plans to speak about the tougher U.S. stand a short time later.
The administration will also slap new sanctions on Syria through an executive order.
The official spoke on condition of anonymity because Obama had not yet released his statement.
As Syrian protesters have called for an end to his regime, Assad has unleashed tanks and ground troops in an attempt to retake control in rebellious areas.