The Obama administration has called for the Syrian government to suspend its diplomatic and consular missions in the United States.
The suspension requires all personnel who are not legal American residents to leave the United States.
White House Spokesman Jay Carney has said that "in consideration of" what Washington claimed was "atrocities" the government of President Bashar al-Assad has committed "we have determined it is unacceptable for individuals appointed by" Damascus to conduct diplomatic or consular operations in the United States.
Meanwhile, Russia has slammed the decision and says it shows the United States is seeking regime change in Syria and is not trying to resolve the crisis through diplomatic channels.
The Russian Foreign Ministry has said the US decision contradicts the agreement reached earlier by Moscow and Washington "to work together energetically on a peaceful solution to the crisis in Syria."
Syria has also condemned the US move, calling it illegal. Damascus says the unilateral move is a clear violation of Vienna Convention that governs diplomatic relations between nations.
On the ground in Syria, the Syrian army has gained full control of the strategic town of Ras al-Ayn in Damascus Countryside. The new gain has come a few days after the army recaptured the strategic town of Yabroud near Lebanon’s border.