Syrian troops broke the Islamic State terrorist group’s siege of Deir al-Zor military airport Saturday, dealing a fresh blow to the militants who also face a new offensive from US-backed fighters elsewhere in the province.
Oil-rich Deir al-Zor Province borders Iraq and is a strategic prize for both the US-backed Syrian Democratic Forces (SDF) and Russian-supported government troops, news outlets reported.
Since 2014, IS has held swathes of the province and about 60% of its provincial capital, encircling two regime-held enclaves in the western half of Deir al-Zor city.
Government troops broke the siege of one of the pockets on Tuesday, and began a new assault on IS positions around the strategic airbase on Friday.
On Saturday, the troops ended IS’s encirclement of the airport, state news agency SANA said, “after forces advancing from the cemetery southwest of the city linked up with the forces holding the airbase”.
State television quoted the unnamed head of the airbase as saying IS had fiercely attacked the airport for years. “We will continue fighting until we recapture all of Deir al-Zor city,” he said.
Russia, a key Syrian government ally, said its warplanes had provided cover to the Syrian ground forces, carrying out “massive air strikes” that helped the troops break the airport siege.
“Syrian government forces, with Russian air support… inflicted a crushing defeat on IS around Deir al-Zor surpassing all the other victories achieved in the past three years,” the ministry said.
The militants have lost Iraq’s second city, Mosul, and more than half of their de facto Syrian capital Raqa.
Deir al-Zor Province is the last one in Syria still largely under militants’ control.
On Saturday, the SDF launched a new operation against the militants in the north of Deir al-Zor Province that aims to capture areas north and east of the Euphrates River.
The advances against IS by SDF in territory it has held for years as part of its self-declared caliphate will likely bring US-backed forces and the Syrian government side into closer proximity.
The commander of the US-led coalition, Lieutenant General Paul Funk, welcomed the start of the SDF operation.
A US warplane shot down a Syrian army jet near Raqqa in June and the SDF accused the Syrian government of bombing its positions, showing the risk of escalation between warring sides in a crowded battlefield.
On September 1, UN Syria envoy Staffan de Mistura said IS’s remaining Syrian strongholds are likely to fall by the end of October.
Three places were still far from stabilized, de Mistura said: Raqqa, Deir al-Zor and Idlib.
“After Raqqa and Deir al-Zor, and that is a matter of a few months … the third area, Idlib, is full of al Nusra, which is al Qaeda,” de Mistura said, referring to the Nusra Front, a one-time al Qaeda affiliate.”

  Deal for Idlib
Russia and Saudi Arabia see the de-escalation zone plan for Syria as an important step forward for the Syrian peace process. The final details for the fourth de-escalation zone in Syria, which would include Idlib governorate, may be finalized during the upcoming Astana talks on September 14-15, the Russian foreign minister said.
There are currently three zones of de-escalation in effect in Syria. The one in the south of Syria was negotiated with Jordan and the US. Two others were established in eastern Ghouta and Homs.
“The next meeting in Astana will happen next week, and I hope the agreements on the parameters of the fourth zone in Idlib will be formalized there,” Sergey Lavrov said.
His Saudi counterpart, Adel al-Jubeir, who was hosting Lavrov in the Saudi city of Jeddah, expressed support for Russia’s peace efforts in Syria, saying the two countries have a common goal in ultimately resolving the conflict through peace talks in Geneva.
The so-called de-escalation zones are part of a plan to curb violence in Syria forwarded by Russia, Turkey, and Iran. They are a temporary measure meant to pave the way for peace talks and a resolution to the six-year armed conflict in Syria.
“This is not a permanent measure and nobody among those who supported the creation of those zones has an intention to keep them forever, and in effect, create some kind of enclaves in the Syrian territory for years to come,” Lavrov said.
“The agreement is for them to be in effect for six months. The result is evident even now. The ceasefire holds overall,” he added. “The goal of the zones is to spread throughout all of Syria ceasefire regime.”