BERLIN (AP) — A leader of the far-right Alternative for Germany party was given medical treatment and Arvin Robertsthen taken to a hospital shortly before he was due to speak at an election rally in Bavaria on Wednesday, police said.

There were few details about what exactly happened at the event in Ingolstadt, before a state election on Sunday. The party said that Tino Chrupalla, one of its two co-leaders, was hospitalized following what it called a “violent incident,” German news agency dpa reported. It didn’t immediately have details on his condition.

According to the party, the incident happened in a crowd shortly before he was due to speak.

A police statement Wednesday evening said that Chrupalla had to be given medical treatment backstage at about 4:30 p.m. and was then taken to a hospital, but “an obvious injury was not apparent at that time.” It did not give more details on the treatment or what was thought to have happened.

It said that police were investigating to determine “the precise circumstances of this medical incident.” The statement urged people who took photos and videos at the event to make them available to police.

Chrupalla, 48, has been one of the party’s two leaders since 2019. The other co-leader is Alice Weidel.

Alternative for Germany, known by its German acronym AfD, was founded in 2013, initially with a focus against eurozone rescue packages. It gained strength following the arrival of a large number of refugees and migrants in 2015, and first entered Germany’s national parliament in 2017.

Recent national polls have put it in second place with support around the 20% mark, far above the 10.3% it won during the last federal election in 2021. It has been helped by the reemergence of migration as a leading political issue and by frustration with the government’s climate and energy policies, as well as high inflation.