(Adds details of ships, deputy minister's comment)
By Gabriela Baczynska
MOSCOW, Sept 6 (Reuters) - Russia is sending more naval vessels to the coast of Syria, state news agencies reported on Friday, in a move Moscow says will help prevent a threatened U.S. attack on its ally President Bashar al-Assad.
The Russian Defence Ministry said in late August it would carry out a routine rotation of its ships off Syria.
But local media said on Friday additional units were also on the way. Interfax news agency quoted an unnamed navy source as saying large landing ship Nikolai Filchenkov was heading for the eastern Mediterranean.
"The vessel will dock in Novorossiysk where it will take special cargo on board and head to the designated area of military service in the eastern Mediterranean," the source said without giving more details.
RIA news agency quoted an unnamed senior navy source as saying on Friday that the frigate Smetlivy would leave for the Mediterranean on Sept. 12-14 and the corvette Shtil and missile boat Ivanovets would approach Syria at the end of the month.
The Defence Ministry declined to comment on the reports but Deputy Defence Minister Anatoly Antonov said on Thursday the Russian navy currently had a "pretty strong group" there.
"The Russian navy does not intend to take part directly or indirectly in a possible regional conflict," he told the state Rossiya 24 broadcaster.
"Our navy vessels are a guarantee of stability, guarantee of peace, an attempt to hold back other forces ready to start military action in the region."
Landing ships Minsk and Novocherkassk and the reconnaissance ship Prirazovye passed through the Bosphorus on Sept. 5. on their way to the Mediterranean and Moscow has also sent missile cruiser Moskva and destroyer Admiral Panteleyev there.
Russia has a small naval facility in the Syrian port of Tartous, its only naval base outside the former Soviet Union.
Western and Arab states seek to oust Assad, and the United States is considering military strikes to punish Damascus for its alleged use of chemical weapons.
Russia, a long-time weapons supplier to Damascus, opposes any U.S. intervention, saying it would lack a mandate from the U.N. Security Council, where Moscow has blocked Western-led attempts to increase pressure on Assad.
The West accuses Russia of protecting Assad and the dispute has overshadowed a G20 summit in St Petersburg this week. (Editing by Andrew Roche)