U.S. military officials in charge of European operations last week suggested Kurdish militants may have played a role in a border incident that left five Turkish civilians dead near the country's southern border.
Mark Toner, a spokesman for the U.S. State Department, said, however, that Washington has "been clear" that incidents along the Turkish-Syrian border were the work of the Syrian military operating under the authority of Syrian President Bashar Assad.
"The onus rests squarely on the Assad regime," he said. "We wouldn't be in this situation if it weren't for Assad's brutal crackdown of a peaceful opposition to the government."
Ankara responded to the border incidents with military force. This week, the government said there was "no point" in trying to discuss the security situation in Syria with a "regime that continues to massacre its own people."
A Syrian rights monitor said at least 500 people were killed last weekend in the country despite calls for a cease-fire to honor the Muslim holiday of Eid al-Adha.
Toner said that, as a result of an anti-government uprising, Syrian forces took defensive action.
"But let's be very clear that it's Assad and his regime that bear responsibility here (for the violence,)" he said.