At least two people have died in a shooting in the eastern German city of Halle, with media and witnesses reporting that the targets were a synagogue and a Turkish restaurant.
"Early indications show that two people were killed in Halle. Several shots were fired," German police said on Twitter on Wednesday.
Max Privorotzki, leader of the Jewish community in Halle, told German newspaper Spiegel that gunmen had tried to enter the local synagogue but security measures in place helped withstand the attack.
Mr Privorotzki said that there were 70 to 80 people present at the synagogue at the time. Wednesday is the Jewish holy day of Yom Kippur.
An eyewitness, Konrad Roesler, told news channel NTV he was in a Turkish restaurant about 600 metres away from the synagogue when "a man wearing a helmet and military uniform" flung a hand grenade at the store.
"The grenade hit the door and exploded," he said.
"[The attacker] shot at least once in the shop, the man behind me must be dead. I hid in the toilet and locked the door."
Two people were also seriously injured during the gun attack and had undergone surgery, a spokesman for Halle's hospital said.
Police said that the perpetrators fled the scene in a car, adding later that one suspect had been arrested.
"Our forces have detained one person," they said. "We remain alert, however. We have deployed forces in and around Halle and are trying to stabilise the situation until we have all the relevant information."
The mayor of Landsberg, 15 kilometres from Halle, told Reuters that two suspects had hijacked a car in the town and were heading towards Munich.
“This is terrible news from Halle,” said Steffen Seibert, spokesman for Chancellor Angela Merkel. “I hope the police catch the culprit or culprits as soon as possible and that no one else is in danger.”
Security expert Rita Katz, director of intelligence group SITE, tweeted that head-mounted camera footage of the shooting was posted on a video game site, in a move similar to the Christchurch massacre.
She says prior to the attack the allegedly shooter says in English the “root of all problems are the Jews".
Anti-terror prosecutors have taken over the investigation, given "the particular importance of the case".
The attack comes hours after a series of raids were carried out across Germany as part of an investigation into threatening believed to have been sent by far-right extremists.
Fears over the growing threat from the far-right were realised earlier this year when a pro-migrant politician from Ms Merkel's CDU party was murdered in his home by a suspected neo-Nazi.
Germany has also been the site of attacks from Islamic extremists in recent years - the most deadly being the Berlin truck attack in 2016.
On Monday, a Syrian man hijacked an articulated lorry and smashed it into cars stopped at a traffic light in the city of Limburg, injuring several people. A 32-year-old man was remanded in custody on suspicion of attempted murder.