BEIRUT (Reuters) - A Syrian army advance against Islamic State in northern Syria has opened a new link between government-held areas in western Syria and the Kurdish-dominated northeast, redrawing the map of the conflict near the Turkish border.

The advance, if sustained, could open a trade lifeline between the northeast, which has 70 percent of Syria’s oil and also includes rich farmland, and the west, where Syria’s manufacturing is based.

Northern Syria is one of the most complicated battlefields in the multi-sided Syrian war that erupted in 2011.

The army advance has taken place to the south of an area where Turkey and its rebel allies are waging their own, rival campaign, carving out a buffer zone to keep Islamic State and Kurdish groups away from the Turkish border.

Syrian government forces have now come to the edge of a swathe of territory dominated by the Kurdish YPG militia, which has mostly avoided conflict with Damascus but is seen by Turkey as an extension of the PKK militant group that has waged a three-decade insurgency on Turkish territory. The YPG’s critics have accused it of cooperating with Damascus in the Syrian war.

The spokesman for the Syrian Democratic Forces (SDF), a militia alliance dominated by the YPG, said the Syrian army’s advance would bring benefits to civilians in the area.

“On the trade front and on the civilian front it is seen as an excellent thing, because now there is ... a link between the entire northern rural area,” spokesman Talal Silo told Reuters.

Now, he said, there was a direct route from the SDF-controlled town of Manbij to the city of Aleppo “via areas controlled by the SDF and areas controlled by the regime forces”.

There was no immediate comment from the Syrian military on its latest advances, but state media said the village of Fikha al Sagira was captured as the army expanded control of areas south of al Bab city.

The city fell to Turkey-backed rebels on Thursday after months of heavy fighting against Islamic State militants.

By taking Islamic State territory south of al-Bab, the Syrian army is seeking to prevent any possible move by Turkey and the rebel groups it supports to expand southwards.

Free Syrian Army (FSA) rebel groups participating in the Turkey-backed ‘Euphrates Shield’ operation also said on Monday they had captured a string of villages east of al Bab.

“INTERESTS OF CITIZEN”

The Syrian Observatory for Human Rights said the army had captured some two dozen villages from Islamic State, bringing it to the edge of SDF-held areas south of Manbij.

The SDF captured Manbij from Islamic State last year with backing from the U.S.-led alliance against the jihadist group.

Silo said residents of the northeast who had previously depended on medical care in Aleppo and Damascus would be able to do so again. “All these matters are in the interests of the citizen,” he said.

The Syrian government still has footholds in YPG-dominated northeastern Syria in the cities of Qamishli and Hasaka. The YPG also controls part of the city of Aleppo, where government forces and their allies defeated rebels in December.

The YPG forms the military backbone of three autonomous areas set up in predominantly Kurdish regions of northern Syria since the onset of the conflict in 2011.

Turkey’s intervention has disrupted the YPG’s plans to link up the two autonomous areas of northeastern Syria with the third one, which is located in northwestern Syria.

The main Syrian Kurdish groups and their allies want to preserve their autonomy in a new federal system of government for Syria. Syrian President Bashar al-Assad opposes the idea.