The U.S. State Department condemned a mortar attack on the Russian Embassy in Syria Thursday afternoon, emphasizing that “those responsible for atrocities on all sides must be held accountable.”

“We condemn any attack against individuals or facilities protected by international law,” State Department spokeswoman Jen Psaki said in a statement.

The mortars have killed one and wounded seven thus far, according to Reuters.

The attack is believed to have been launched by anti-government rebels in Syria. Russia has been a strong supporter of the regime of President Bashar Assad, and central Damascus, where the embassy is located, has been a frequent target of rebel mortar attacks.

Russia's foreign ministry referred to the attack as “terrorism” and called for the perpetrators and instigators to be punished.