Media reports suggest several dozen Scud missiles and launch ramps were moved from a military base near Damascus, designed to protect the weapons systems from strike.
The move complicates even further the tough decision facing President Barack Obama, who is weighing whether to go forward with an attack on Syria after reports appeared to prove Bashar al-Assad's government used chemical weapons on its own people, despite opposition from allies and within Congress.
Secretary of State John Kerry is expected to make a statement Friday afternoon.
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