The U.S.-backed Syrian Democratic Forces holds about 27 percent of the country's territory.
The missing cache includes torahs and tapestries.
Hours after the Israeli military urged citizens to take shelter and President Donald Trump left the Iran deal, new strikes were reported in Syria.
As the Syrian military and its allies advance on the ISIS' last stronghold south of Damascus, the jihadis' tactics grow more bloody.
They persevered because education for them is a matter of life and death.
ISIS has agreed to surrender its final stronghold south of Damascus, but the Syrian military and allies continue to fight until talks are finalized.
Tehran's foreign ministry has warned: "Tel Aviv will be punished for its aggressive action."
The Syrian military has forced the insurgents of eastern Ghouta to either surrender or leave, but pro-Assad forces expected a fight with ISIS in the south.
Russia's Ministry of Foreign Affairs has called out Heather Nauert for ridiculing Moscow's bombardment in Syria.
Russian Defense Minister Sergei Shoigu said the ceasefire would be in place from 9 a.m. to 2 p.m. daily, beginning February 27.
One leading Russian senator said, "It would be good if the Americans, along with us, took part in liberating eastern Ghouta from the terrorists."
Then why did Trump launch a missile strike against the Shayrat airbase in Syria?
The US must not allow itself to be blackmailed by a Kurdish terrorist outfit.
One of Syrian President Bashar al-Assad's closest advisers said many challenges still lie ahead, including reconstruction and the presence of foreign powers.
The 59th Damascus International Fair opens despite ongoing violence in the outskirts of the Syrian capital. It's the first such event in five years.
The claims come a week after the Pentagon announced it observed what appear to be preparations for a new chemical attack at a Syrian government airfield.
Despite thousands of "spontaneous returns" by displaced Syrians, the United Nations doesn't think the country is safe yet.
Russia says the downing of the Syrian warplane was 'a cynical violation of Syria's sovereignty.'