Psaki said, as she has before, that if reports of chemical weapons use prove true, the president has a range of responses available.
Later, a senior defense official told CNN that "the military continues to refine options for Syria to be prepared for whatever the president might request down the line."
U.N. High Commissioner for Human Rights Navi Pillay said the matter is "of utmost urgency" and the "allegations are exceptionally grave."
Pillay urged the government and opposition to allow investigators "to examine the site of the alleged attacks without any delay or obfuscation."
Meanwhile, a U.S. defense official said Friday the United States has added one more destroyer to the eastern Mediterranean fleet.
The USS Ramage arrived to replace the USS Mahan, but the Mahan is going to stay around a bit longer, so temporarily there will be four in the fleeet. The USS Gravelly and USS Barry are still there.
These ships are all equipped with the Tomahawk Land Attack Missiles, a long-range subsonic cruise missile used to attack land targets.