A woman stands in front of her destroyed house in the town of Mughor al-Mir, one of the three towns as the last strongholds of rebels, largely those affiliated with the al-Qaida-linked Nusra Front, in the Western Ghouta countryside of Damascus, capital of Syria, on Dec. 29, 2017. (Xinhua/Ammar Safarjalani)

MOSCOW, Feb. 7 (Xinhua) -- The Nusra Front terrorist group, an offspring of Al-Qaeda, is the main source of destabilization in Syria, a Russian Defense Ministry spokesman said Wednesday.

"The militants of this terrorist group, receiving supporting weapons and other materials from the third parties, seek to derail the peace process in the de-escalation zones, attempting to squeeze out the formation of the moderate opposition," Major-General Igor Konashenkov said in a statement.

Russia is deeply concerned by the fact that the Nusra Front has recently obtained portable air defense systems (MANPADS), which can also be used outside Syria and beyond combatting military aircraft.

On Saturday, militants of the Nusra Front shot down using MANPADS a Russian Su-25 jet fighter when it overflew a de-escalation zone in the province of Idlib in northwestern Syria.

The pilot, Major Roman Filippov, managed to jettison, but blew himself up with a grenade after being surrounded by militants.

Shortly after the incident, the Russian Air Force group in Syria, in retaliation, carried out a massive strike against an area in Idlib in northwestern Syria, which was controlled by the Nusra Front, killing at least 30 militants.

Konashenkov said that the Russian Ministry of Defense was working to establish the types of MANPADS obtained by terrorists and channels for their delivery.

The spokesman recalled that the Nusra Front carried out a mass attack by shock drones earlier this year against Russia's Hmeymim and Tartus military bases in Syria, using technical solutions previously unavailable to terrorists.

"All this confirms our fears that the terrorists of the Syrian branch of Al-Qaeda became an obedient instrument in the hands of one or a group of technologically advanced countries that are not satisfied with Russia's key role in the liberation of Syria from the Islamic State," Konashenkov concluded.