MOSCOW - Russia has so far withdrawn from Syria a total of 35 military aircraft, including warplanes and helicopters, the Russian Defense Ministry said on Monday.

The ministry said in a statement that two Mi-8AMTSh helicopters have returned to their permanent deployment base in Russia's Novosibirsk region in southwestern Siberia.

These are in addition to the 33 aircraft already withdrawn from Syria, the statement said.

Russia began withdrawing troops from the war-torn Middle East country in December under an order by Putin announced during his visit to the Hmeymim military airfield in Syria.

Putin said at a Kremlin ceremony last month that Russia had pulled out 13 warplanes, 14 helicopters and 1,140 troops.

Sergey Surovikin, the commander of Russian forces in Syria, said that in the first stage, Russia planned to pull out 23 warplanes, two Ka-52 helicopters, and part of its special operation forces, field hospital troops and demining teams.

However, Russia will keep two military bases in Syria, the Hmeymim military airfield and the Tartus naval base, under an agreement with the Syrian government.

Russia has participated in anti-terrorist operations in Syria since September 2015 at the request of the Syrian government.