The Syrian army on Sunday captured the Tharda Mountains in the southern rim of Deir al-Zour province in eastern Syria, securing the airbase of Deir al-Zour, a military source told Xinhua.

The capture of the Tharda Mountains has secured the vicinity of the airbase of Deir al-Zour, as the mountains function as the airbase's first defense line.

A day earlier, the Syrian army and allied troops broke the Islamic State (IS) siege on the airbase, just a week after lifting the IS' three-year siege on the capital city of Deir al-Zour.

Speaking on condition of anonymity, the source said that the United States had bombed Syrian army in the Tharda Mountains in September 2016, which facilitated the IS control over it.

source: Xinhua