Counter terrorism police in Britain say that the assailant in last week's attack on a synagogue in the city of Manchester that left two people dead had pledged allegiance to the Islamic State group.

U.K. police have been given extra time to question four people arrested on suspicion of terror offenses after an attack on a synagogue in northwest England.

British police say one of the two men killed in a car and knife attack on a synagogue in the city of Manchester may have been killed by a bullet fired by a police officer.