White House spokesman Josh Earnest says those responsible for serious human rights and international law violations must be held accountable.
The State Department has cited reports Syrian President Bashar Assad's regime and pro-government forces destroyed Bayda, Syria, with mortar fire, then stormed the town, executing entire families.
Earnest wouldn't comment on an overnight airstrike Israeli warplanes carried out around the Syrian capital. The strike was the second attack by Israelis in three days. Officials say it targeted a shipment of advanced, Iranian-made missiles believed to be bound for Lebanon's Hezbollah militants.
Earnest spoke with reporters aboard Air Force One inflight from Washington to Columbus, Ohio.