The Latest: Footage shows last moments of London attack
Dramatic footage from London's Borough Market shows three attackers viciously stabbing a man just before police converge and shoot them all dead.
Police have arrested six men in actions directed against terror in the U.K. as a tense nation begins voting in a national election.
Detectives from London police's counterterrorism command raided properties in east London on Thursday, detaining three people on suspicion of the commission, preparation or instigation of terrorism offenses.
Police are hunting any possible accomplices in the attack in which three men mowed down pedestrians on London Bridge and then launched a knife rampage.