British police said on Friday they may have accidentally shot two victims, including one who died, in their attempts to bring under control an attack on a Manchester synagogue during Yom Kippur, the holiest day in the Jewish calendar.

In Thursday's attack, two men, Adrian Daulby, 53, and Melvin Cravitz, 66, were killed after a British man of Syrian descent drove a car into pedestrians and then began stabbing several people outside Manchester's Heaton Park Hebrew Congregation Synagogue.

The attacker, whom armed officers shot dead at the scene, was not carrying a firearm, said Greater Manchester Police Chief Constable Steve Watson, though one of those killed suffered a gunshot wound.