Spain is facing international anger as it apparently prepares to refuel a flotilla of Russian warships due to step up strikes against the beleaguered city of Aleppo.
Politicians and military figures condemned the support from a Nato member, while the head of the alliance indicated Madrid should rethink the pit stop.
Warships from an eight-strong group led by the carrier Admiral Kuznetsov will take on fuel and supplies from the port of Ceuta, a Spanish enclave in north Africa, after passing through the Straits of Gibraltar on Wednesday morning,
Jens Stoltenberg, Nato's secretary general, said the carrier group, which passed through the English Channel last week, could be used to bomb civilians in the city.
He said: “It’s for each nation to decide whether these ships can get supplies and be fuelled in different harbours along the route towards the eastern Mediterranean.
“But at the same time we are concerned, and I have expressed that very clearly, about the potential use of this battle group to increase Russia’s ability and to be a platform for air strikes against Syria.
“This is something I have conveyed very clearly before and I repeat those concerns today. I believe that all Nato allies are aware this battle group can be used to conduct air strikes against Aleppo and Syria.”
Spain regularly refuels Russian warships at the North African port, which it says is not covered by Nato treaties. At least 60 Russian military craft have made technical stops at the Spanish enclave since April 2010, when the naval base was opened up to serve ships from other nations.
Sir Gerald Howarth MP, a former Defence Minister, said it would be “wholly inappropriate” for a Nato member to refuel the Russian vessels.
He said: “Spain is a member of Nato and Nato is already facing challenges from Russia, not least in the Baltics.
He went on: “The Russians stand accused of indiscriminate bombing in Aleppo and Syria and it would be inappropriate to render them military assistance.”
Lord West, a former head of the Royal Navy, added: “There are sanctions against Russia and it’s an extraordinary thing for a Nato ally to do.”
Guy Verhofstadt, the former Belgian prime minister, said on Twitter: “Spain signed EU statement on Russian war crimes in Aleppo last week; today helps refuel fleet on way to commit more atrocities. Seriously?”
Naval sources said the Kuznetsov itself would not dock in Ceuta, but its accompanying tanker and escorts could.
Spain’s Foreign Ministry told the Telegraph requests from the Russian navy were considered on a “case by case basis, depending on the characteristics of the ship concerned”.
A spokesman said: “Russian navy vessels have been making calls in Spanish ports for years”.
But in an indication Madrid was feeling increased diplomatic pressure not to help Moscow, the Spanish government said it was reviewing the Russian request.
The spokesman said: “The latest requested dockings are being revised at the current time in light of information we are receiving from our allies and from the Russian authorities.”
Russia’s military visits are estimated each to bring in more than £270,000 to the city through a combination of mooring fees, fuel and supplies, and the money spent by sailors during their time onshore.
Lt Gen Evgenny Buzhinsky, who oversaw relations with Nato as a former head of the Russian ministry of defence's international treaty department, described the stop in Spain as entirely routine.
"As long as the Spanish government hasn't banned it, it is a commercial matter like any other vessel stopping to take on supplies, even if it concerns military ships," he said. He said it is not unusual for Russian navy vessels take on supplies in Nato countries, including Greece and Italy.
Meanwhile the RAF on Tuesday night scrambled Typhoon jets to escort two Russian Bear bombers off the coast of Scotland.
