Warships led by the aircraft carrier Admiral Kuznetsov are expected to take on fuel and supplies at the Spanish port of Ceuta after passing through the Straits of Gibraltar on Wednesday morning, The Guardian reported.

Late on Tuesday night, El Pais reported that the Spanish ministry of foreign affairs was reviewing the permit issued to the Russian flotilla to stop at Ceuta.

Read alsoRussia may use Admiral Kuznetsov carrier group for more airstrikes against Aleppo - StoltenbergAt a meeting of defense ministers in Paris, Spain's representative, Pedro Morenes, said the government would seek clarification from Russia about "the purpose and destination" of the ships, which he confirmed had "prior authorization" to stop at Ceuta.

NATO secretary-general Jens Stoltenberg warned on Tuesday that Russian warships heading for Syria could be used to target civilians.