DAMASCUS, April 21 (Xinhua) -- The Syrian army has been on a crushing offensive against the Islamic State (IS) south of the capital Damascus after the militants got divided over accepting a deal for their evacuation, state TV reported on Saturday.

The shelling has intensified on the Hajar al-Aswad area south of Damascus in the western Ghouta countryside of the capital, said the report, adding that the Syrian forces destroyed arms depots in its military operation aiming at eradicating the terror-designated groups completely from southern Damascus areas.

The Syrian forces also targeted supply routes of the IS militants in Hajar al-Aswad and killed tens of the militants.

This comes as the militant groups in that area thwarted a deal for their evacuation out of Hajar al-Aswad and nearby areas to the Syrian desert.

The sound of shelling and airstrikes could be clearly heard in Damascus, with the army stressing resolve to eliminate the militants south of Damascus if they maintained their stance to stay in Hajar al-Aswad and nearby areas.

The IS entered those areas in 2015 and the military operation started after the army completely secured the Eastern Ghouta countryside of Damascus, with the last rebel batch left their last strongholds in the Douma district a week ago.

The IS group has lost major strongholds late last year, but they are still holding some pockets south of Damascus and the in the remote eastern desert region of Syria.