The Syrian army has killed scores of foreign-backed armed mercenaries and seized their weapons during an ongoing campaign across the war-hit country.

The Syrian army has killed scores of foreign-backed armed mercenaries and seized their weapons during an ongoing campaign across the war-hit country.

Syrian government forces launched security operations against the militants in the provinces of Damascus, Aleppo, Deir Ezzor, Homs, Idlib and Daraa on Tuesday and killed a large number of them, the official SANA news agency reported.

They also captured a large number of machine guns, sniper rifles, rocket launchers, mortar shells and explosive devices.

In Aleppo, the army units destroyed several cars full of weapons and ammunition, and killed a number of militants.

In Idlib, the national military destroyed eight cars equipped with anti-aircraft guns.

Moreover, government troops attacked groups of “terrorists” in the Damascus suburbs of Khan al-Sheeh and Daraya city, killing all of them.

The Syrian army has recently conducted successful clean-up operations across the country, inflicting heavy losses on the militants.

Recent investigations by various media outlets have found that the foreign-backed militants are taking amphetamine stimulants to stay on their feet in exhausting battles against Syrian government forces, Al-Alam website reported.

Al-Qaeda linked groups are also said to be using stimulant drugs extensively as they launch many attacks at night and are engaged in gruesome battles.

Syria was hit by a violent unrest since mid-March 2011, where the Syrian government accuses foreign actors, mainly the Saudi Arabia and Turkey, of orchestrating the conflict by supporting the militant opposition groups with arms and money.

On December 9, Syria urged the United Nations to stop Saudi Arabia from "supporting Al-Qaeda-linked militants" and fanning the flames of "terrorism" in the country.