Russia's Defence Ministry said on Thursday the four Russian cruise missiles fired at Syria from the Caspian Sea had reached their targets, Interfax news agency reported, refuting US officials and media that the missiles had crashed in Iran.

A US government source said Russia had been flying cruise missiles over Iran into Syria in attacks on rebels fighting Syrian President Bashar al-Assad.

"In contrast to CNN we do not talk with reference to anonymous sources," Interfax quoted Russian Defence Ministry spokesman Major General Igor Konashenkov as saying. "We show the launch of our rockets and the targets they struck."

*The story was edited by Ahram Online.