There has been an explosion at the main entrance the Spassky Gate to the Russian government complex, the Kremlin, in Moscow.
The Interior Ministry says a man drove his car across Red Square at high speed knocking down barriers and jumped from it moments before it exploded in front of the gates.
He was taken to hospital, as were three guards.
The man was later identified as Ivan Orlov, a sixty-five year-old journalist, who worked for a nationalist magazine.
The police said Mr Orlov would be given a psychiatric examination, while investigations continued into whether the incident was a criminal act.
From the newsroom of the BBC World Service