ACCRA, Ghana — The Obama administration is readying new sanctions on Syrian President Bashar Assad’s regime and its allies as U.S. Secretary of State Hillary Rodham Clinton heads to Turkey for weekend talks with top Turkish officials and Syrian opposition activists.

Senior U.S. officials traveling with Clinton as she wraps up a nine-nation Africa tour in Ghana and Benin before flying to Turkey today said the fresh sanctions aimed at hastening Assad’s ouster were imminent.

The sanctions are expected to complement existing penalties, which have targeted Assad’s inner circle, including his entire Cabinet, along with Iranian individuals and entities that have been providing support to the regime.

They come as Clinton prepares for Saturday’s discussions in Istanbul that will focus on forming a “common operational picture” with the Turks and Syrians to guide a democratic transition in post-Assad Syria, the officials said.