MADRID (Reuters) - Spain is reviewing a request by a Russian flotilla to refuel in its North African enclave of Ceuta, the foreign ministry said as Madrid drew criticism from NATO allies for assisting warships they believe could be used to target civilians in Syria.

NATO is monitoring the eight-strong carrier battle group from northern Russia on its way to the eastern Mediterranean, where alliance officials fear it will launch fighter bombers to hit rebels in northwestern Syria early in November.

"The latest stopover requests are being reviewed at the moment based on the information we are receiving from our allies and from Russian authorities," the ministry said in a statement.

In Brussels, NATO Secretary-General Jens Stoltenberg said it was up to Spain to decide whether to refuel a Russian tanker traveling with the carrier battle group, but that NATO had expressed its concern to allies, including Madrid.


"We are concerned about the potential use of this carrier group to increase attacks against civilians in Aleppo," Stoltenberg said, referring to the war-ravaged Syrian city where government forces are besieging its rebel-controlled eastern half. "All allies are aware of our concerns."

British Defence Secretary Michael Fallon told reporters in Brussels that London would be "extremely concerned that any NATO member should consider assisting a Russian carrier group that might end up bombing Syrian civilians ... On the contrary, NATO should be standing together."

Britain has raised concerns with Spain over the possible refueling of Russian warships on their way to Syria, a spokeswoman for Prime Minister Theresa May said on Wednesday, adding that the situation was being monitored closely.

There was no immediate Russian comment on the matter.


Former Belgian prime minister Guy Verhofstadt, who leads the Liberal bloc in the European Parliament, 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?"

Spain granted permission for three Russian navy ships to dock in Ceuta several weeks ago, according to El Pais newspaper. It quoted Spanish diplomatic sources as saying permission would be revoked if Spain confirmed that the three ships were part of the Russian fleet headed for Syria.

The Foreign Ministry said Spain had been allowing Russian navy vessels to dock in Spanish ports for years, treating such requests on a case-by-case basis.

It was unclear on Wednesday whether any of the Russian ships would actually call in at Ceuta. The MarineTraffic web site showed the Osipov, a Russian cargo ship that is one of the fleet's support vessels, had sailed well past Ceuta.

The naval group, which passed through the English Channel on Friday, is made up of Russia's sole aircraft carrier Admiral Kuznetsov, as well as a nuclear-powered battle cruiser, two anti-submarine warships and four support vessels, likely escorted by submarines, according to NATO officials.

The naval deployment is carrying dozens of fighter bombers and helicopters and is expected to join around 10 other Russian vessels already off the Syrian coast, diplomats said.

Washington's envoy to NATO said Russia was within its right to move vessels through international waters. But U.S. Ambassador Douglas Lute raised concern that the aircraft carrier would be used to contribute to bombing of civilian targets around Aleppo.

(Reporting by Rodrigo de Miguel, Sarah White and Adrian Croft; Editing by Mark Heinrich)