DAMASCUS, June 4 (Xinhua) -- The Syrian army on Saturday entered the administrative borders of the northern province of al-Raqqa, the de facto capital of the Islamic State (IS) group, a monitor group reported.

The Syrian army backed by Russian air cover managed to cross the administrative borders of al-Raqqa, just days after unleashing a wide-scale offensive on the route between the town of Athriya in the central province of Hama, and the al-Tabaqa town in al-Raqqa countryside.

The Syrian forces are trying to reach the al-Furat lake and the road connecting al-Raqqa with the northern province of Aleppo, said the Syrian Observatory for Human Rights.

Only 40 km separate the army forces from the targeted areas, said the UK-based watchdog group.

The battles, which broke out on Thursday, have so far killed 26 IS militiamen and nine government forces.

If the army succeeded, the IS will be besieged by the Syrian army in the south and southwestern parts of Aleppo, while the U.S.-backed Syrian Democratic Forces (SDF) rebels will be besieging the terror group from the west.

On Thursday, pan-Arab al-Mayadeen TV said the Syrian army and allied fighters unleashed a wide-scale offensive, aiming at capturing the town of Tabqa in countryside of al-Raqqa.

Even though there is no declared cooperation between the attacks by the U.S.-led forces and the Syrian government ones supported by Russia, but analysts believe Russia and the United States have apparently reached an agreement to weaken the IS.

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