A gunman who killed two people in Germany live-streamed the attack, mirroring the Christchurch massacre.
On Wednesday (local time) the man filmed himself ranting about the Holocaust, immigration and feminism before opening fire.
He targeted a synagogue and a kebab shop in the eastern German city of Halle.
The footage was shared on video platform Twitch.
It has since been removed from the site, reports The Independent.
Several shots were fired and the suspected assailant then left in a car, police said in a tweet.
They urged residents to stay in their homes or indoors.
A short time later, police reported that one person had been arrested. They gave no information on that person.
Pictures from the scene showed a body lying in the street behind a police cordon.
Police didn't give any further information, but said officers were out in force in the city hunting down the suspects.
They gave no details about the target of the attack and there were varying reports.
The Bild and Mitteldeutsche Zeitung newspapers reported that the shooting took place near a synagogue - Wednesday is the Jewish holy day of Yom Kippur.
A person interviewed on n-tv television said he had been in a kebab shop when he saw a man with a helmet and military jacket, who he said fired shots into the shop.
Police said shots were also fired in Landsberg, about 15km from Halle. It wasn't clear whether that incident was related to the shooting in the city.
The railway station in Halle, a city of 240,000, was closed down as a precaution amid the police operation.