Two people have reportedly been killed in a shooting in the eastern German city of Halle, local police say one person has been arrested.
Several shots were fired and the suspected assailants then fled in a car, officials said in a tweet.
Local media reported a hand grenade and a submachine gun were used during the incident, which reportedly took place near a synagogue.
Wednesday marks the Jewish holiday of Yom Kippur, although a suspected motive for the shooting was not given by officials.
Chancellor Angela Merkel's spokesman, Steffen Seibert, lamented what he called "terrible news from Halle" but government officials said they had no information on the attack.
Authorities tweeted they had arrested one person, shortly before 2pm local time (1300 BST).
Local people have been urged to stay in their homes as further information becomes available.
A eyewitness interviewed on local 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 a shop.
Photos from the scene appeared to show a bullet casing on the ground, officers had encircled with green paint to mark its location.
Further photos from the scene showed armed personnel mounting a ladder to climb over a wall.
Police said that shots were also fired in Landsberg, a town near Halle. It wasn't clear whether that incident was related to the shooting in the city.
Deutsche Bahn, Germany's national railway operator, said in a social media post that the local railway station had been closed in the aftermath of the attack.
Halle is a city of 240,000 people, around one hour south of the country's capital, Berlin.