Police said they had arrested a 31-year-old man at an airport in northwest England on Thursday in connection with last month's Manchester synagogue attack, in which two people died.

The man was detained on suspicion of commission, preparation and instigation of acts of terrorism, Greater Manchester Police said.

He was detained at Manchester Airport after arriving on an inbound flight and remains in custody for questioning, the force added.

A total of seven people have now been arrested over the attack at the Heaton Park Hebrew Congregation Synagogue on October 2.

A 30-year-old man arrested on October 9 on suspicion of failing to disclose information under the Terrorism Act remains on bail, say police.

Five of those arrested have been released without charge.

In a visit to a synagogue on Thursday unrelated to the latest arrest, Prime Minister Keir Starmer acknowledged the Jewish community's "sense of insecurity" in the wake of the attack and the October 7, 2023, Hamas attack in Israel.

Noting he had extended family in Israel through his wife, the UK leader said he did not want "anybody here or elsewhere to feel that Britain... is not a safe and secure place for them."

"That is simply intolerable, unacceptable, and I have to do everything I can to turn that around," he told worshippers at Bushey United Synagogue, north of London.

Syrian-born UK citizen Jihad al-Shamie started his attack early last month in Manchester by driving his car at security staff and the external gates of the synagogue.

Worshippers had gathered there for Yom Kippur, the holiest day in the Jewish calendar.

Wearing a fake suicide belt, he then stabbed father-of-three Melvin Cravitz, 66, multiple times and tried to storm the synagogue before being shot dead by police.

Cravitz died from multiple knife wounds inflicted by Shamie, an inquest heard.

Adrian Daulby, 53, died from a single gunshot wound to the chest fired by a police officer responding to the situation. (AFP)