A knife attack against two Jewish men in north London on Wednesday was declared a terrorist incident, and a man remains in police custody after being arrested on suspicion of attempted murder.

The attack has raised fears across Britain’s Jewish community, which has endured several crimes in recent months that are being investigated as antisemitic. Last month, ambulances owned by a Jewish charity were set alight in the same area of London, and two synagogues have been targeted by arson attacks.

Here’s what we know.

What happened in the latest attack and who was injured?

Late on Wednesday morning, the police were called to reports of a man attacking people with a knife in the Golders Green neighborhood, a center of Jewish life in London.

Two Jewish men, aged 34 and 76, were treated at the scene for stab wounds, according to the police. Both were taken to a hospital and are in stable condition.

Hours after the attack, the police released body camera footage that showed officers responding at the scene. A man with a knife can be seen approaching the police before he is stopped with an electric stun gun and falls to the ground.

What have the police said?

The police have indicated that this attack was part of a surge of violence against Jewish people and institutions in London. Mark Rowley, the commissioner of the Metropolitan Police, the city’s main force, told reporters on Wednesday that the police “have seen a rise in racist and antisemitic hate crime.”

Mr. Rowley also alluded to a pattern that has emerged in recent weeks in a series of attacks against the Jewish community across Europe that investigators and counterterrorism experts are investigating for potential links to Iran or other state actors.

“While I cannot comment on live investigations, we know that some individuals are being encouraged, persuaded, or paid to commit acts of violence on behalf of foreign organizations and hostile states,” Mr. Rowley said.

A shadowy online Islamist group, calling itself Harakat Ashab al-Yamin al-Islamiyya, claimed responsibility for this attack in a video shared on the Telegram messaging app some hours after it took place on Wednesday.

The group provided no evidence for its claim. It had previously claimed responsibility for a series of arson attacks across Europe that began on March 9. British authorities have not confirmed that the group played a role in the stabbings on Wednesday and experts have urged caution over the claim. Investigators are trying to determine whether the group has any links to Iran or its proxies, though the police and security officials have so far stopped short of directly linking the group to Iran.

What is known about the suspect?

The suspect in Wednesday’s attack is a 45-year-old British national who was born in Somalia, according to the police, and who came to Britain as a child. He was arrested on suspicion of attempted murder and was initially taken to a hospital. Once he was discharged later on Wednesday, he was taken to a London police station.

“He has a history of serious violence and mental health issues and the investigation is ongoing,” Mr. Rowley said.

The suspect may also be linked to an incident earlier Wednesday morning in south east London, the police said, where a man armed with a knife is believed to have had an altercation a person at a residential address. The suspect there is believed to be the same person arrested in Golders Green.

He had previously been referred to the country’s Prevent program, the police said on Thursday. Prevent is a government-funded initiative that aims to stop people from becoming terrorists and to divert people before they are radicalized into extremism.

The suspect’s name has not been released. This is normal practice in Britain before charges are filed.

How is the British government responding?

The day after the attack, the government announced an additional 25 million pounds, around $33.7 million, for more police patrols and security for Jewish communities. There had already been an increase in funding to enhance security measures after a deadly attack at a synagogue in Manchester, in northern England, in October.

Shabana Mahmood, Britain’s home secretary, told the broadcaster Sky News on Thursday, “There are very real risks that the community is living through.”

Prime Minister Keir Starmer met representatives from criminal justice agencies Thursday morning and promised a “swift and visible” response to those who carry out such attacks.

“There’s no getting away from the fact that this was not a one-off,” Mr. Starmer said. “This has been a series of attacks on our Jewish community, particularly in recent weeks, and there is a very deep sense of anxiety, of concern about security, about safety, about identity, frankly.”