© Sputnik
A tank in the Syrian city of Deir ez-Zor where the Syrian army continues fighting the Islamic State September 12, 2017.
Oilfields and a natural gas-processing plant southeast of the Deir-ez-Zor airbase have come under the control of the Syrian Army, RIA Novosti reports.

It was also reported, that advance detachments of the Syrian Army have taken control of the strategically-important hills near the Karrum Mountain ridge to the southeast of the Deir ez-Zor air force base. An RT contributor on scene confirmed the information.

The terrorists are resisting fiercely, bombarding the advanced detachments of the Syrian Army with mortars, heavy machine guns and sniper rifles, RIA Novosti reports.

The artillery of the Syrian Army is destroying the firing positions of Islamic State (IS, former ISIS/ISIL), supporting the advancement of the army and allied forces to Deir ez-Zor.

Last week the Syrian Army, supported by Russian forces from the air, finally managed to break the siege of an important airbase, Deir ez-Zor, retaking it from IS.

"On September 9, following a massive airstrike by the Russian Air Force, Syrian government forces overcame the fierce resistance of ISIL terrorists in the area surrounding an airfield to the southeast of Deir ez-Zor," the Russian ministry said in a statement.

Syrian state TV reported that the Teym oilfield was recaptured from IS. This eastern part of Syria is an oil-rich area. IS ammunition warehouses were identified by the Syrian Air Force during the operation, Syrian Army General Ahmad Sulaiman told RT, saying that the military also "listened in to meetings in which the terrorists planned attacks inside and around Deir ez-Zor."

"With the help of Russian air power, the Syrian Air Force struck these places ahead of the arrival of Syrian government troops. This weakened ISIL's ability to attack and to call in reinforcements from Raqqa and Palmyra," the Syrian Army commander said.

In June, IS controlled around a quarter of the country. In the past three months, IS has lost around half of those territories, however. It still partly holds territories near Hama and Homs in western Syria.

Some 40 IS terrorists, including the so-called "emir of Deir ez-Zor," were killed as Russian warplanes struck and wiped out an underground command center and communication unit near the city, the Russian Defense Ministry said last Friday.

The Russian Air Force was acting upon the intelligence it received from several sources indicating that a meeting of senior IS militants was about to take place in one of the underground command centers on the outskirts of Deir ez-Zor.

"The effective actions of the Russian Air Force speeded up the lifting of a siege from the city of Deir ez-Zor and allowed the Syrian troops to begin liberating the city," the ministry said in a statement on Friday.

Among the senior militants killed is internationally wanted Abu-Muhammad al-Shimali (also known as Tirad Al-Jarba), the self-proclaimed "emir of Deir ez-Zor," the ministry said, adding that the militant's death has been confirmed.

According to the ministry, the killed IS commander was involved, among other things, in transferring "IS terrorists through territories of Turkey, European, North Africa, Persian Gulf states and Australia."

Apart from smuggling the recruits into Syria, al-Shimali was named by "several European intelligence agencies" as one of the organizers of the fatal November 2015 Paris attacks, the ministry added.

Syrian Army troops, backed by Russian air support, managed to break the three-year-long siege of the city of Deir ez-Zor on September 5, following fierce clashes with IS terrorists on its outskirts.

Deir ez-Zor Governor Muhammed Ibrahim Samra told RT's Ruptly agency last week that the long-awaited lifting of the siege became "peak of excitement" for soldiers and civilians, suffering from shortage of water, food and electricity. It has also finally allowed Russia to send humanitarian aid convoys to the area, as previously all the aid was delivered by air.