Russia's cities have been put on high alert today following warnings of a possible terrorist attack on public transport targets.
Extra police are being deployed on the streets, in train stations and other possible target sites.
The added security follows what the Russian security services say was information "from foreign partners" about possible terrorist attacks on ground transport and in the subway.
Police, security agents and bomb-sniffing dogs have been deployed to check the city's subway system, the Russian news agency RIA Novosti said. Russia's main cellular phone operators suspended services in the Moscow subway.