Russia's embassy in London says its website crashed in a suspected hacking attack just before Prime Minister David Cameron begins the first visit by a British leader to Moscow since the 2006 killing in London of a Kremlin critic.
The embassy said it had set up a "mirror" website to meet the increased interest of the public and media for information before Cameron flies to Russia on September 11.
The embassy said in a statement that its website "was brought down by a suspected DDoS" or distributed denial-of-service, attack.
A DDoS attack is one in which hackers flood a website with requests for information, making it unavailable to legitimate users.
Britain's relations with Russia have been soured by a dispute over the 2006 murder in London of Aleksandr Litvinenko, a former Russian intelligence agent who died from poisoning by radioactive polonium-210.
Russia has refused to extradite Andrei Lugovoi, an ex-KGB bodyguard Britain wants to prosecute for Litvinenko's murder, plunging bilateral ties to a post-Cold War low.
Relations have improved since Cameron took office in 2010.
compiled from agency reports