The EU-wide arms ban means that European companies are prevented from providing services to organizations that may be arming government forces in Damascus.
William Hague, the UK Foriegn Secretary, had revealed during questioning in parliament today that the ship was headed back to Russia. Hague also said that he had discussions with Russia and strongly discouraged that any country should attempt to supply arms to Syria following violence in the country.
The new row comes only weeks after Putin's re-election as President and relations have continued to sour between Russia and Western governments over the diplomatic deadlock. Russia has repeated claims that there were no weapons aboard the ship and denies that it is supplying the Syrian government with any weaponry or military supplies.