A GroenLinks alderman has stepped down from his post in Hilversum after being accused of writing an anti-semitic email to a local resident.

Bart Heller was responding to an email to a Hilversum family, sent on behalf of the Israeli embassy, and requesting a demonstration of support for the Bibas family who died after being taken hostage by Hamas.

The letter asked the council to light up the town hall in orange (the colour of the Bibas children’s hair) in solidarity.

Heller, unaware the mail was addressed to the local council as a whole, took it upon himself to answer the mail, and replied the family of the two boys had “suffered immeasurable and indescribable grief”.

However, he said, but “he couldn’t help but think of the situation in Gaza” where he said over 15,000 children had been killed since the Israeli invasion.

He implied that any show of solidarity should also include these children. He then said his reaction should be forwarded to the Israeli embassy.

Dutch chief rabbi Binyomin Jacobs accused Heller of anti-semitism and contacted Hilversum mayor Gerhard van den Top about the issue. The mayor then brought the letter up in the council where Heller’s response was criticised for its “contents and tone”.

Heller said in his letter of resignation he regretted sending the mail but would not retract any of its contents. If his stance on Gaza stood in the way of his job it “would be a negligible price to pay compared to what the children in Gaza suffer every day,” he said.

The Nieuw Israëlitiesch Weekblad called Heller’s mail “rabidly anti-Israel” and accused him of using figures “straight from Hamas”. By “equating the member of the Jewish community with the state of Israel”, he is guilty of anti-semitism according to the IHRA definition subscribed to by the Netherlands,” the paper said.

According to The Rights Forum, which advocates for Palestinian rights, Heller is “a victim of the Israel lobby”.

Local GroenLinks chairwoman Marleen Remmer said in a reaction the group does not consider Heller’s mail anti-semitic but agreed it “should never have been written and sent”.