Russia's defence ministry on Monday denied reports that it is building a new military base in Syria, where it has pursued a bombing campaign for the past four months.
"There are no new airbases or additional aerodromes for Russian warplanes in the Syrian Arab Republic, and no plans to create any," defence ministry spokesman Igor Konashenkov told Russian news agencies.
Western media outlets have reported that both Moscow and Washington are establishing covert military bases near Syria's border with Turkey.
The reports followed a claim by Turkish President Recep Tayyip Erdogan that up to 200 Russian soldiers were working on a runway at an airbase in the northeastern Syrian city of Qamishli on the Turkish border.
Britain-based monitor the Syrian Observatory for Human Rights alleged that Russia had sent a number of engineers to the border town to strengthen the runway and increase the capacity of the airport there.
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But Konashenkov on Monday said only "absolute morons" could seriously discuss alleged Russian activity in Qamishli, saying the reports were an attempt to "cover up the build-up of a large Turkish military force" at the Syrian border.
Reports of Russia's alleged move into Qamishli came as Ankara and Moscow are embroiled in their worst diplomatic crisis in years after Turkey shot down a Russian war plane on November 24.
Russia officially operates a naval facility in the Syrian port city of Tartus, as well as an airbase on the outskirts of the coastal city of Latakia.
Moscow launched a bombing campaign in war-torn Syria at the request of long-time ally President Bashar al-Assad on September 30.
The defence ministry said Monday that Russian jets had bombed 484 "terrorist infrastructure" targets in 169 combat sorties between January 22 and January 24.
The latest strikes, according to the Russian military, had helped Syrian armed forces in the Latakia region "liberate more than 92 square kilometres of territory and 28 communities from terrorists" in the past 24 hours.
The Russian defence ministry says its strikes are targeting the Islamic State group and other extremist organisations, but the West has accused Moscow of targeting more moderate groups that oppose the Assad regime.