Germany on Wednesday said it had summoned the Iranian ambassador over an attempted arson attack on a synagogue in 2022 that Berlin believes was planned with the help of Tehran.

A German-Iranian national was in December sentenced to two years and nine months in prison over the plot to attack a synagogue in the western German city of Bochum.

The 36-year-old, identified only as Babak J., had planned to target the synagogue but ended up throwing an incendiary device at an adjacent school building. No one was injured.

In handing down the verdict, the Duesseldorf court said the attack had been planned with the help of "Iranian state agencies".

The foreign ministry on Wednesday said in a post on X, formerly Twitter, that it had summoned the Iranian envoy after receiving a written justification of the judgement.

"We will now immediately share the judgement with our European partners and the EU institutions and examine further steps," the ministry said.

Germany had already in December summoned Iran's charge d'affaires over the plot.

Germany has grown increasingly alarmed in recent years about rising anti-Jewish sentiment eight decades after the end of the Holocaust.

Anti-Semitic acts have increased sharply in the country amid the latest turmoil in the Middle East, according to the Federal Association of Research and Information Centres on Anti-Semitism (RIAS).