British police said on Friday that one of the men who died in the Manchester synagogue attack was accidentally shot by police and that one of the injured was also shot by officers.

Two worshippers – Adrian Daulby, 53, and Melvin Cravitz, 66, – died in the attack on Thursday and three others were seriously injured. Police have identified the assailant as Jihad Al-Shamie, 35, a British citizen who came to the U.K. as a young child from Syria. They have also arrested three people.

Tributes and flowers have been piling up near the Heaton Park Hebrew Congregation Synagogue as people across Britain expressed their grief and outrage at what police have described as a terror attack.

Police shot and killed the attacker, who was armed with a knife. On Friday, Manchester Police Chief Constable Stephen Watson said one of the men who died had been accidentally shot, as well as one of the injured. The death and injury were the “unforeseen consequence of the urgently required action taken by my officers to bring this vicious attack to an end,” he said.

Prime Minister Keir Starmer visited the site on Friday with his wife, Victoria Starmer, who is Jewish. And at Westminster, flags in the House of Commons at half mast.

“The good and decent people of Manchester stand with you and we always will. There is no place for hate here and we will not have it,” said one noted posted on fence close to the synagogue.