WASHINGTON (AFP) – The United States must “stand up and act” to punish the Syrian regime and cannot resort to isolationism in the face of “slaughter,” Secretary of State John Kerry told lawmakers Tuesday.

“This is not the time for armchair isolationism. This is not the time to be spectators to a slaughter,” Kerry told the Senate Foreign Relations Committee.

“Neither our country nor our conscience can afford the cost of silence,” Kerry said, according to prepared remarks.

“We have spoken up against unspeakable horror. Now we must stand up and act,” he added.

Kerry made an impassioned case for punitive strikes against Syria over its alleged use of chemical weapons after President Barack Obama put off military action to first ask Congress for approval.