ISIL killed at least 58 Syrian government troops and militia as the militants put up fierce resistance to a Russian-backed offensive against some of its last bastions.
In a statement, the extremists put out a statement claiming to have killed scores of regime fighters in the area. They also released what they said was an audio recording of their leader Abu Bakr Al Baghdadi urging resistance, the first such interjection from him in nearly a year.
Syrian troops pushed through the vast desert that separates the main cities of the west from the Euphrates Valley this summer and broke a three-year ISIL siege of government enclaves in the eastern city of Deir Ezzor earlier this month. The attacks on Thursday targeted government forces around Deir Ezzor and on their supply lines through the Sukhna area from the west. According to the UK-based war monitor, the Syrian Observatory for Human Rights, the first attacks were carried out against checkpoints manned by loyalist troops in Al-Shula, a village near Deir Ezzor and then moved on to checkpoints along the length of the motorway from Al-Shula to south of Sukhna.
Syrian state media made no mention of the army's losses, but said its troops "confronted an attack by the terrorist Daesh group on the highway between Deir Ezzor and Palmyra, deep in the Badia desert."
State news agency SANA said the army had "inflicted heavy losses on the ranks of the terrorists," adding that army units were "currently working to clear remaining Daesh terrorists from the area and secure the highway for traffic."
The attacks by the jihadists came as they face multiple offensives against the last bastions of their self-proclaimed caliphate — by US-backed fighters and Russian-backed government forces in Syria and by troops and paramilitaries in Iraq.