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.

"It is currently believed that the suspect, Jihad Al-Shamie, was not in possession of a firearm and the only shots fired were from GMP's Authorized Firearms Officer," the Greater Manchester Police (GMP) statement said.

"It follows therefore this injury may have been sustained as a tragic and unforeseen consequence of the urgently required action taken by my officers to bring this vicious attack to an end," Greater Manchester Police Chief Const. Steve Watson said in a statement.

Police added that one of four people injured and currently receiving treatment in hospital also suffered a gunshot wound.

Watson said it is thought that both shooting victims were close together behind the synagogue door, as worshippers tried to prevent the attacker from gaining entry to the Heaton Park Congregation Synagogue.

The police complaints watchdog said it was carrying out an investigation into what happened.

Earlier on Friday, police named the two men killed in the attack as Adrian Daulby, 53, and Melvin Cravitz, 66, both local residents.

Britain declared Thursday's attack, which occurred on Yom Kippur, the holiest day on the Jewish calendar, as a terrorist incident. The suspect drove a car into pedestrians and then stabbed a security guard. 

'Everything feels a little bit shaky'

Prime Minister Keir Starmer has deployed more police to synagogues.

On Friday, Starmer visited the site of the attack and spoke with members of the Jewish community. He did not make any public statements, but said the previous day that Al-Shamie wanted to "attack Jews because they are Jews."

When Deputy Prime Minister David Lammy spoke at a vigil outside the synagogue on Friday he was confronted by some members of the community. 

"Our country, those of all colours, all faiths and none, stand with you," Lammy said.

"We stand against all those who would minimize or coddle or obfuscate anti-Jewish hate."

Britain, like other European countries as well as Canada and the United States, has recorded a sharp rise in antisemitic incidents in the nearly two years since Gaza conflict began.

Last month, Britain announced it was recognizing a Palestinian state in the hope of reviving peace for Palestinians and Israelis, a decision decried by Israel as a "huge reward to terrorism."

Police said they could find no records that al-Shamie, a 35-year-old British citizen of Syrian descent, had been referred previously to the country's counter-radicalization scheme, Prevent. 

In a statement on Facebook, the family of al-Shamie said they were in "profound shock" and wanted to distance themselves from what they called his "heinous act."

On Friday morning, there was a heavy police presence at the scene of the attack, with debris still lying in the street and bunches of flowers left nearby.

Dawud Taj, a 28-year-old from Manchester, said the government should have done a better job at protecting people.

"There's an atmosphere in the air," he told Reuters as he walked to the city centre, "and everything feels a little bit shaky."

Calls for protest to be postponed

Meanwhile, Britain's government and the police on Friday urged organizers of a planned pro-Palestinian protest in London this weekend to cancel or postpone the event.

Interior Minister Shabana Mahmood urged protesters to "take a step back" for a few days to give the Jewish community time to grieve and process what has happened.

Lammy also urged anyone considering marching on the weekend to "stop and stand back." 

WATCH | A recap from Thursday's news conference: 

Saturday's demonstration has been organized by Defend Our Juries to oppose the British government's July decision to ban the pro-Palestinian group Palestine Action under anti-terrorism laws, making it a crime to be a member.

The Metropolitan Police said they wanted to deploy every available officer to protect communities affected by the Manchester attack but were instead having to prepare for a gathering of more than 1,000 people in London's Trafalgar Square on Saturday in support of Palestine Action.

In response to the police, Defend Our Juries said they condemned the attack on the Jewish community in Manchester. They said it was the police's choice whether or not to make arrests at the protests.

"We urge you therefore to choose to prioritize protecting the community, rather than arresting those peacefully holding signs in opposition to the absurd and draconian ban of a domestic direct action group," Defend Our Juries said.

In the hours after the attack on Thursday, several pro-Palestinian protests took place in British cities. Police clashed with demonstrators near the prime minister's official residence at Downing Street, leading to 40 arrests.