The Foreign Ministry said earlier media reports about the use of nerve gas under Russian supervision during clashes in the town of Homs were "dirty lies".

"We categorically deny these fabrications. They only confirm that an informational war (is) launched over the Syrian problem. Its masterminds despise nothing, allowing themselves slander against Russia. Someone obviously finds it hard to overcome the desire to respond with dirty lie to our principal position in the Syrian issue," said a statement from the ministry.

Moscow reiterated its firm position on the settlement of internal crisis in Syria, saying it should be resolved within the sphere of international law and through peaceful, political and diplomatic means.

Russia is committed to the Chemical Weapons Convention which bans the use, production and storage of chemical weapons, said the statement.

Several Middle East media have cited Syrian opposition sources as saying that the regime has been using chemical weapons with the help of hired experts from Russia and Iran.