According to western diplomatic sources only 20 bombing aircraft and one personnel-transport plane have returned to Russia from Syria since Moscow’s partial withdrawal announcement on March 13.

They say that a total of 24 aircraft -- including 12 Sukhoi Su-24s four Su-30s four Su-34s and four Su-35s -- remain deployed in the country.

Advanced-technology Sukhoi Su-30 Su-34 and Su-35 aircraft all of which are now deployed in Latakia’s Khmeimim Airbase are used to carry out bomb-runs capable of causing enormous destruction.

The continued presence of 12 Russian Sukhoi Su-24 bombers in Syria means Russia has maintained the ability to carry out heavy bombardments across wide swathes of territory.

On Tuesday Sergey Rudskoy chief of the Russian General Staff’s main operations department said Russian airpower may begin targeting groups that fail to comply with a cessation-of-hostilities agreement that went into effect in Syria late last month.

According to Rudskoy Russian military officials proposed this to their U.S. counterparts at a March 18 meeting in Oman but the latter had declined to consider the plan.

- Buildup

Since September of last year Russia has bolstered its military assets in the coastal areas of Syria generally relying on a Caspian Sea-Iran-Iraq air corridor.

At a time when international criticism of the Russian military buildup in Syria was mounting Moscow on Sept. 30 of last year began extensive air operations in the country within the context of "fighting terrorism".

Turkey and western powers for their part accused Russia of striking moderate Syrian opposition groups rather than terrorist targets.

Russia currently maintains Su-24s Su-25s and Su-30s at the Khmeimim Airbase which is controlled by Syria’s Assad regime along with Mi-24 attack helicopters and unmanned aerial vehicles.

What’s more following the downing of a Russian aircraft that violated Turkish airspace near the Syrian border on Nov. 24 Russia began deploying S-400 air defense systems in Syria.

Russian warships meanwhile remain docked in Latakia’s Port of Tartus which is also controlled by the Assad regime.

Critics say that Moscow has used both the Khmeimim Airbase and its naval assets to strike at positions held by moderate opposition groups.

On Feb. 27 Russia scaled down its air campaign in Syria after the cessation-of-hostilities agreement came into effect.

On March 13 Russia announced the reduction of forces deployed in the country although the announcement was met with a degree of skepticism by both moderate Syrian opposition groups and a number of international actors.

Kremlin spokesman Dmitry Peskov for his part has said the Russian military presence at both the Khmeimim Airbase and the Port of Tartus would be maintained.

Col. Steve Warren chief spokesman for the U.S.-led coalition against the Daesh terrorist group asserted on March 16 that only "a small handful" of Russian aircraft had left Syria following Moscow’s partial withdrawal announcement.