France and Britain expressed their concern Thursday about the Russian military buildup in Syria after Moscow said it would conduct naval drills in the eastern Mediterranean.
French Defence Minister Jean-Yves Le Drian, speaking on a day of intense European diplomacy on the conflict, called on Moscow to justify the "very significant" Russian buildup.
Le Drian said: "We know what everyone can see, the very significant buildup of Russian forces both in the port of Tartus and above all, with the setting-up of a military airport to the south of Latakia and the presence of several fighter jets, combat helicopters and drone capacity there."
He said if Russia's main intention was "to protect President Bashar al-Assad", it should say so.
British Defence Secretary Michael Fallon, speaking alongside Le Drian after they held talks, said he was "equally concerned" by the Russian buildup in Syria "which will only complicate what's already a very complicated and difficult situation".
Fallon warned that the focus on Russia should not divert attention from the need to deal with Islamic State jihadists operating in Syria.
"We should not divert our focus from the need to deal with the threat of Daesh, the very direct threat to Britain and France, and the instability that Daesh is posing in both Syria and Iraq," he said, using an Arabic acronym for Islamic State (IS).
The foreign ministers of France, Germany and Britain are meeting with EU foreign affairs chief Federica Mogherini on Syria in Paris on Thursday.
Russia's defence ministry said Thursday it will hold naval drills in the eastern Mediterranean region this month and next month.
It said the exercises had been planned since the end of last year and it did not link them to the Syria conflict.
Russia has supported the Syrian regime throughout the four-year conflict that has claimed some 250,000 lives.