The military alliance fighting in support of Syrian President Bashar al-Assad said on Saturday Israel will witness a "severe and serious" response to its "terrorism" from now on.
In a statement, the alliance said Israeli claims that a drone entered Israeli airspace were a "lie".
The statement said Israel attacked a drone base in central Syria. The alliance added that drones had left the T4 air base in the morning to conduct routine operations against Islamic State in the Syrian desert.
"When the base was targeted our aircraft were still flying over the town of Sokhna, towards the desert," the statement said. Sokhna is a town northeast of the city of Palmyra in central Syria.