Russia has begun withdrawing significant amounts of military equipment and troops from Syria after the fall of former Syrian President Bashar al-Assad, according to U.S. officials and a Western official familiar with the intelligence.

Officials described the Russian withdrawal as "large-scale" and significant, and said it began last week, but it is not clear whether it will be permanent, the officials told CNN.

US and Western intelligence indicate that Russian officials were trying to determine whether Hayat Tahrir al-Sham was open to some kind of negotiated settlement that would allow Russia to remain in some of its key bases, according to the sources.

These bases include the Russian Hmeimim air base in Latakia, and the port of Tartus.

Kremlin spokesman Dmitry Peskov said at a news conference last week that Russia was in contact with militants in Damascus.

"We have to maintain contact with those who control the situation on the ground because, as I mentioned, we have facilities and personnel there," he said.

Two US officials said the Russians had begun moving naval assets from Syria to Libya.

The official said that if they do not obtain a base in a Libyan port, and if they are forced to abandon Tartus in Syria, the Russians will be left without a Mediterranean port to project their power on NATO's southern flank.

The defense official said that losing Tartus, even temporarily, would make it difficult for Russia to move weapons between Russia and Africa.

CNN reported last week that Russia appeared to be loading and preparing aircraft to leave its military bases in Syria, according to satellite images captured by Maxar on Friday.