DAMASCUS, Jan. 18 (Xinhua) -- The Islamic State (IS) group said it made new progress on Wednesday in the battles against the Syrian army in the eastern province of Deir al-Zour, capturing strategic locations.

IS' Amaq news agency said the IS militants captured the electricity company building and its vicinity in the mountain area, northwest of the Deir al-Zour airbase, where the IS fighters took key areas around it.

It added that one of its militants blew himself up in a position of the Syrian army in the vicinity of the company, killing 15 and injuring others.

Other activists said the IS also controlled the tanks battalion in that area.

State news agency SANA said Wednesday that the Syrian army backed with air cover heavily struck positions of IS in areas the terror group has recently infiltrated in Deir al-Zour.

It said the Russian and Syrian warplanes carried out several aristrikes on the IS position in the factories area and Tamin hilltop, as well as the graveyards area and other areas in Deir al-Zour.

The airstrikes, according to SANA, led to the destruction of the IS vehicles and killed many of them.

Meanwhile, the Syrian Observatory for Human Rights said Wednesday that smoke is still bellowing over Deir al-Zour, as the IS terrorists have burned tires and crude oil to blind the Syrian and Russian warplanes, which have been heavily striking the IS positions in Deir al-Zour, since the group unleashed its major offensive against the government positions in that area earlier this week.

The Observatory said the IS militants made important gains on Monday, capturing areas around the Deir al-Zour airbase, which enabled the group to cut the road between the base and the city, just a day after the militants captured the mountain overlooking the city.

This progress is dangerous as the airbase is the only lifeline left for the city, which has been besieged by IS since early 2015.

Cutting the road is not only cutting a lifeline but also divides the government-controlled parts of the city into two parts, eastern and western, which tightens the noose on over 500,000 civilians in the city.

The IS next step is apparently attempting to capture the airbase, and in near future to storm the government-controlled parts of the city, if there was no surgical military operation to put an end to the marching IS terrorists.