The missiles exploded in the neighborhoods of al-Qusur and al-Joura in western Deir ez-Zor.
The city of Deir ez-Zor, which is still held by Syrian government forces, has been under siege from Daesh since July 2014. The residents of Deir ez-Zor and the servicemen only receive food and humanitarian aid via air-drops. On January 30, the United Nations resumed aid deliveries after a two-week pause.
Since 2011, Syria has been engulfed in a civil war, with government forces fighting against numerous opposition and terrorist groups, including al-Nusra Front and Daesh, banned in a range of countries, including Russia.
Moscow has been conducting a counter-terrorist campaign in Syria since September 30, 2015, at President Bashar Assad's request.