Syria's army chief of staff, Gen. Abdullah Ayoub, said Thursday that the military has unleashed a broad offensive against rebel-held areas across the country, buoyed by the Russian air support, according to the state news agency SANA.

"Today the Syrian armed forces have started a wide-scale offensive with the aim of eliminating the terrorists' positions and liberate the areas and towns that have suffered from terrorism and its woes and crimes," Ayoub said in a statement.

The senior Syrian military officer said Russia's air strikes have weakened the rebel groups, while the army now can have a stronger position.

He also said that the army has formed a new force, including a battalion called the Intrusion Squad.

"After the Russian air strikes..., the Syrian army took the initiative and formed a force equipped with guns and munitions, most importantly the Intrusion Squad," he said.

Ayoub, however, stopped short of naming the areas where the Syrian army is on the offensive.

Meanwhile, a military source told SANA that the Russian warplanes in cooperation with the Syrian air force carried out a series of airstrikes against the positions of the Islamic State (IS) in several areas in the countryside of the northern province of Aleppo, killing "hundreds of terrorists," destroying tens of armored vehicles and two Grad rocket launchers as well as a "huge" weapon depot.

A day earlier, the Syrian army recaptured 70 km of rebel-held territory in central province of Hama, as the Syrian ground force waged attacks Wednesday under the cover of Russian war jets, the pan-Arab al-Mayadeen TV reported.

About 50 km of the retaken territory were under the control of the Jaish al-Fateh group, or the Conquer Army, an alliance of several jihadi groups, mainly the al-Qaida-linked Nusra Front, said the report, adding the other 20 km were under the control of other rebel groups.

The Hama battle marks the first instance where the Syrian military ground forces have carried out a broad offensive under the direct Russian air support.

The army hopes to fully secure the road between Hama and the central province of Homs under Russian airstrikes against the rebels.

The offensive also aims to separate the countryside of Hama from the countryside of the northwestern of Idlib, which is largely under the Jaish al-Fateh control.

The Russian warplanes started on Wednesday its air strikes against rebel positions in several Syrian areas, marking the first Russian military involvement in the war on terrorist groups in Syria.

Damascus has confirmed that the Russian air raids came upon the request of Syrian President Bashar al-Assad, according to SANA.

Moscow has recently amplified its assistance to the Syrian military forces, and Russian officials promised more of such aid, including specialists, to Damascus.

Russia says the increase in military supplies aims to combat terrorism in accordance with international law.

The state-run TV reported Tuesday that thousands of rebels are fleeing their positions toward Turkey and Jordan, as a result of the Russian and Syrian airstrikes

The rebels have suffered "great losses," which led to a "collapse in their morale," as thousands of them fled toward Turkey and Jordan and part of them fled toward Europe, the TV said.

The report collaborated with what a senior military officer told Xinhua that "the Russian air strikes have a tangible efficiency."

He said the militants have not only fled their positions to Turkey, but many IS members have fled from al-Raqqa province, the de facto capital of the IS, toward Iraqi territories.

The strikes have raised the ire of the Syrian rebels, as several rebel groups called on regional countries to form an alliance against the Russian-led coalition pummeling them, according to a statement released on Monday.

In the statement, over 41 rebel groups, including the powerful Ahrar al-Sham Movement, deemed the Russian military intervention in Syria as an "occupation," and urged regional countries to form a coalition in order to face the Russian-led group which also includes Iran, Iraq and Syria.

The statement reflected the rebel groups' resentment, who are on the receiving end of a strong pounding by Russian air strikes.

The Syrian wing of the banned Muslim Brotherhood also issued a statement, calling on the Syrians to wage jihad against what they called the "flagrant Russian occupation of Syria."

"We, as the Muslim Brotherhood, affirm that we are in the face of an outright, clear Russian occupation, through the entry of Russian military forces to Syria... We stress that the concept of resisting is a legitimate duty," the statement read.