A security officer has died and five people were injured after an attacker opened fire outside the headquarters of Russia's spy agency in Moscow.
The shooting happened near the building of the Federal Security Service (FSB), formerly known as the KGB.
It confirmed that one of its officers had died in the attack and that the lone gunman did not manage to enter the premises.
The shooting happened shortly after President Vladimir Putin - a former head of the KGB - held his annual news conference and while he was at a concert for security forces in the Kremlin.
The FSB building is on Lubyanka Square, about half a mile from Red Square.
The service said the gunman had been 'neutralised' by armed officers - a term usually used by officials when an assailant was killed - and they were now working to find out his identity and motive.
Russian television channel, RT TV, reported the intelligence services have said the incident was "an act of terrorism", although the authorities have not confirmed they were treating the incident as a terror attack.