The United States is "deeply concerned" about reports that airstrikes and fighting resulted in the deaths of dozens of civilians in Yarmouk, an area of Damascus home to 150,000 Palestinian refugees, the State Department said Monday. "These latest attacks mark a significant and alarming escalation of the conflict in Syria," State Department spokeswoman Victoria Nuland said in a statement. "In addition to the suffering endured by the Syrian people, the United States is concerned about the situation of the more than 500,000 Palestinian refugees in Syria who are also increasingly suffering from the escalating violence. The Government of Syria should allow all humanitarian actors full and unfettered access in order to protect and assist the victims of the conflict," Nuland said.