Details of the proposed strategy were not revealed but sources said the list of potential targets inside Libya was updated as recently as last week.
The Obama administration has been under increasing pressure to track down the attackers, believed to be linked to al-Qaida, who overran the compound last fall and killed four Americans, including Ambassador Chris Stevens.
The current course of action includes a "capture or kill" operation that could involve U.S. troops entering Libya in some form, the sources said.
Other sources said there had been no orders given to commence an operation, and there were concerns among planners that a U.S. raid could damage the fledgling Libyan government that overthrew Moammar Gadhafi. It was unclear if the Libyans would be involved in any operation by the Americans.