LONDON -- Police confirmed Thursday afternoon that the attack outside the Heaton Park Hebrew Congregation Synagogue on Middleton Road in Crumpsall, Manchester, has been declared a terrorist incident.

At a news briefing, Counter-terrorism Policing Assistant Commissioner Laurence Taylor said three people, including the suspect who was shot dead by police, had been killed, while three others remain in serious condition.

Taylor added that police believe they know the attacker's identity but cannot confirm it at this stage due to safety concerns at the scene. He also confirmed that two further arrests had been made.

He stressed that police forces are stepping up patrols at synagogues and other Jewish sites across the country to provide reassurance. Counter-terrorism officers are working with the security services to build a full intelligence picture in the coming days and weeks.

Greater Manchester Police Chief Constable Sir Stephen Watson later told reporters that the suspect drove a car directly at worshippers outside the synagogue before attacking people with a knife. The suspect was also wearing what appeared to be a suicide vest, which was later found not to contain explosives.

Watson said there were a large number of worshippers attending Yom Kippur services at the time, but "thanks to the immediate bravery of security staff and the worshippers inside, as well as the fast response of the police, the attacker was prevented from gaining access."

Earlier, British Prime Minister Keir Starmer said in a statement that "additional police assets are being deployed to synagogues across the country."

Police said officers were called at 9:31 am local time after reports that a car had been driven at pedestrians and a man had been stabbed. Firearms officers opened fire at 9:38 a.m., fatally shooting the suspect.

Manchester Mayor Andy Burnham told the BBC that people should avoid the area but reassured the public that "the immediate danger appears to be over."