Authorities in Berlin have detained a teenage Syrian refugee after a man was stabbed near the city’s Holocaust Memorial late Friday – as divisive rhetoric swells over Germany’s immigration policy, ahead of a consequential national election.

The suspect, a 19-year-old Syrian man, was living in Germany legally. Germans head to the polls Sunday after a campaign dominated by debate about migration.

Concern is growing over the far-right Alternative for Germany party’s rise ahead of the German election. Its U.S. supporters include Elon Musk and JD Vance.

The leading candidate, Friedrich Merz, a conservative who has adopted many of the AfD’s hard-line positions on immigration, used his closing statement of the debate to promise his voters that he would never allow the AfD into his government. Under him, he said, the firewall would hold.