The first Russian troops returned home Tuesday from their deployment in Syria, beginning a partial withdrawal from a mission widely seen as decisive in swinging the war in favour of President Bashar al-Assad's regime in Damascus.

Some were welcomed by small crowds holding patriotic banners in ceremonies with Soviet-era music in the background. Others were greeted by high placed military officials.

On a surprise visit to Syria on Monday, Putin ordered the start of a pullout of Russian troops, saying their task in the war-torn country had been largely completed.

Russian state television showed images of servicemen back in the far corners of their country, from Dagestan in the North Caucasus to Ivanovo in Central Russia and Murmansk inside the Arctic Circle, throughout the day.

"The battalion of military police from the southern military district (of Russia) deployed to the Syrian Arab Republic has been flown by two military planes to Makhachkala (the capital of Dagestan) airport," the Russian army said in a statement.

The crews of Tu-22M3 bombers returned to Murmansk, in the north of Russia, and to a military airport in North Ossetia before flying out to their permanent base in the central Kaluga region, the army said.

The crew of an A-50 surveillance aircraft flew back to their home base in Ivanovo region where they were met by commanding officers and relatives.

Putin's declaration on Monday was the third announcement of a partial withdrawal since troops were deployed in 2015. He did not clarify how many soldiers will be returning home this time but said both Russia's airbase Hmeimim and naval facility in Tartus would continue to function.

The commander of Russian troops in Syria, Sergei Surovikin, said 23 planes and two helicopters as well as special forces and medical units will return home in the near future.

- 'Up to a month' -

Putin, who said last week he would seek a fourth term in a poll in March, was welcomed at Russia's Hmeimim airbase by Assad.

It was the first trip to Syria by a Russian head of state since president Dmitry Medvedev in 2010. Putin continued from there to Cairo and Ankara to meet heads of state for talks.

RBK news agency cited sources as saying that Russia will pull out two-thirds of its contingent, both personnel and equipment, from Syria, which could take up to a month.

Russia first intervened in the Syrian conflict two years ago with air strikes in support of ally Assad targeting both the Islamic State group and other jihadists as well as rebels fighting government troops.

The size of the Russian deployment in Syria is not known but independent Russian military expert Pavel Felgenhauer told AFP that up to 10,000 troops and private contractors could have taken part in the conflict.

- A 'political war' -

Another Russian military expert Alexander Golts told AFP the intervention in Syria had "exhausted its potential as an instrument of pressure on the West" and threatens to throw Russia into further international isolation.

"In the current failure of foreign policy, it is important for Putin to appear as a military victor and a leader of a global power in the eyes of Russian citizens who will vote for him in a few months," said Golts.

The decision by Putin, who has led Russia since 2000, to seek a fourth term in March's presidential election, was no surprise but ensures a continuation of his Syria policy.

"This war began for political reasons," said Golts. "The aim was not war on terrorism but to come out of political isolation after Ukraine and to support Assad. Since it began as a political war, it will end with a political decision taken by the Russian authorities."