BERLIN: German police said Thursday they had arrested four suspects over a foiled attack on a synagogue on Yom Kippur, the holiest day of the Jewish year.

The case revived memories of an attack two years ago outside a synagogue in the eastern German city of Halle, when a neo-Nazi gunman sought to storm the Jewish temple while worshippers were inside marking Yom Kippur.

There was a huge police deployment late Wednesday at the synagogue in the western city of Hagen, which was forced to cancel an event over the threat.

"There was a danger of an attack on the synagogue in Hagen," said Herbert Reul, the interior minister for the state of North Rhine-Westphalia, adding that police forces "likely prevented it".

Investigators were searching sites in the city, said police on Twitter, adding that a 16-year-old Hagen resident figured among four people arrested.

Both Spiegel weekly and Bild daily had reported without quoting sources that a foreign intelligence service had passed on a tip that a 16-year-old Syrian was planning an explosives attack on a synagogue.

In the 2019 attack, a bolted door at the synagogue was the only thing that prevented the assailant from carrying out the bloodbath.

After failing to gain entry, he shot dead a female passer-by and a man at a kebab shop.

The gunman, Stephan Balliet, was sentenced to life in prison in 2020 over the assault that nearly became the country's worst anti-Semitic atrocity since World War II.

Anti-Semitic crimes have risen steadily in Germany in recent years, with 2,032 offences recorded in 2019, up 13 percent on the previous year.

They have sparked soul-searching in Germany, which has placed a huge emphasis on atoning for the murder of six million European Jews by Adolf Hitler's Nazi regime during World War II.

The arrival in parliament of the far-right AfD, whose leaders openly question Germany's culture of historical remembrance, has contributed to the change in atmosphere.