Maybe it wasn’t halal.

Mayor Eric Adams gathered with around 50 Muslim “supporters” to celebrate the Prophet Muhammad’s 1,500th birthday Thursday — in what was also billed as an endorsement event for his re-election campaign.

But some attendees told The Post they were unaware the City Hall gathering was meant to be an endorsement announcement, saying they thought they were there to fete the annual Mawlid-un-Nabi festival.

“We were invited here because it’s prophet Muhammad’s 1,500th birthday, so thinking that, we came here to support the mayor,” Imam Mouhamed Mountakhka Sakho said in an interview after the event.

“But you know, politicians are politicians. Wherever they go, they will show their color. But we were not here for this [endorsement],” he said.

The press conference largely focused on the prophet’s birthday, which the festival commemorates, with no direct talk of backing Adams’ campaign, though some of the Muslim community leaders praised the mayor and one person was heard calling out “four more years.”

Several other attendees expressed the same sentiment as Sakho. 

He later clarified that he was invited through a WhatsApp group with other imams and received a flyer that only mentioned the prophet’s birthday but nothing about the gathering being a campaign event.

An advisory sent by Adams’ campaign proclaimed, “Leaders of New York City’s Muslim community and religious leaders will endorse Mayor Eric Adams for re-election during the annual Mawlid-un-Nabi festival at City Hall.”

Adam Azam, who helped organize the event, said that while his group, Muslim Community of New York, was endorsing Adams, other attendees may have been unaware of the campaign aspect due to finding out about it on social media. 

“Mayor Adams was asked by members of the Muslim community to be endorsed and celebrate the anniversary,” the campaign said in a statement.