DAMASCUS  -- Syrian troops have started to storm the rebels' key town of Yabroud, north of the capital Damascus, with "heavy and focused" shelling, local media reported on Friday night.

"The Syrian army is entering the town of Yabroud from all directions and advancing on all hubs of the town," the report said, adding that the troops have recaptured all of building blocks at the entrance of the town and its surrounding.

"The armed groups are expected to collapse within hours," the report said.

Earlier in the day, local media said the Syrian army troops had advanced in the orchards of Yabroud, tightening its control over the eastern entrance and the northeastern edge of the town, which is bordering Lebanon.

Meanwhile, the pan-Arab al-Mayadeen said fighters of al-Qaida- linked Nusra Front had erected roadblocks in the town of Flaita, west of Yabroud, and near the Lebanese borders. They tried to prevent rebel fighters from abandoning their positions in Yabroud after the wide-scale offensive of the Syrian army.

In mid-February the army started a major offensive to recapture Yabroud by securing its surroundings before pressing into the town itself.

Yabroud, some 80 km north of Damascus, is deemed as an important stronghold of armed rebels due to its location. The town is on the slope of the mountainous Qalamoun region and near the Lebanese town of Ersal, where the rebels obtained weapons and medical treatment.

Yabroud's rugged terrain and ancient caves also gave them shelter from government air raids.

Military experts said that by capturing Yabroud, the government forces can secure the international road connecting Damascus to the central province of Homs and some provinces on the Mediterranean coast. They could then deter the flow of car bombs into neighboring Lebanon.