"We have been gradually withdrawing from the military logistics transportation market, in due compliance with our previous commitments. The Group will not participate in the tender process initiated by NATO in its existing configuration," Volga-Dniepr said in a statement.

Relations between Moscow and NATO have become increasingly strained.

NATO secretary-general Jens Stoltenberg on Saturday called on Russia to "exercise responsibility" in the Syrian conflict.

However Volga-Dniepr, a world leader in the movement of oversize and heavy air cargo, said the reason for the break with NATO was that the group "is focused on the growth of its business in the civil commercial sector and continuing to extend the scope of its niche products."

The decision means the Russian carrier will not attempt to extend its contract for the provision of its Antonov 124s to ten NATO armies, a project called the Strategic Airlift Interim Solution (SALIS).

That contract, which had been renewed each year since 2006, will now lapse at the end of 2018.

NATO responded with its own statement, saying it had been informed of the decision by Volga-Dniepr and that it is working with the nations affected "to explore options to meet their future airlift requirement from January 2019 onward".

The ten NATO nations involved in the SALIS deal are Germany, France, Belgium, the Czech Republic, Hungary, Luxembourg, Norway, Poland, Slovakia and Slovenia.

The withdrawal of Volga-Dniepr will especially be a problem for France due to delays in the delivery of, and technical and budget problems with, European aviation giant Airbus' new A400M military transporter which has left it very dependent on the Antonov 124s for overseas missions, notably in Africa's Sahel region.

A French parliamentary report in March 2017 highlighted this "very heavy dependence" on Russian and Ukrainian military transport planes.

The Antonov 124, developed in the Soviet era, has a larger cargo capacity than the A400M, allowing it to transport helicopters and tanks.

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