The tunnel dug under the neighborhoods of the Eastern city of Deir Ezzur.
Also on Tuesday, Syrian fighter jets launched heavy airstrikes on so-called Islamic State gathering centers near the Eastern city of Deir Ezzur, army sources said, adding the air assault slowed down militants' movements in the region.
"The Syrian warplanes bombed ISIL's positions in Al Thardah Mountain (Jabal Thardah) near airport and Panorama district, claiming the lives of several terrorists.
ISIL's military hardware also sustained major damage in the syrian Airstrikes.
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