The man shot dead Friday by undercover police at London's Stockwell Tube station was not connected to the investigation into the attempted terror attacks.
A Scotland Yard spokesman said: "For somebody to lose their life in such circumstances is a tragedy and one that the Metropolitan Police Service regrets."
The fatal shooting took place when armed officers shot the man, named as Brazilian Jean Charles de Menezes, as he tried to board a train at the underground station.
He had emerged from a nearby house that was under surveillance because of a suspected link to Thursday's attempted bomb attacks on three Tube trains and a bus.
He apparently tried to get on a train before he was, according to witnesses, shot five times in the head by an officer with an automatic pistol.
Earlier, Metropolitan Police Commissioner Sir Ian Blair said the dead man was "directly linked" to anti-terror operations, Sky News>/i> reported.
