Two people were killed and several injured in a shooting in the eastern German city on Wednesday, which including the targeting of a synagogue.
German Interior Minister Horst Seehofer has said a shooting in eastern Germany that left two people dead was an anti-Semitic attack, adding federal prosecutors who have taken on the investigation thought there were signs that it could be a right-wing extremist attack.
Germany's public prosecutor general has taken on investigating the deadly shooting in Halle because it poses a "specific national threat".
Two people were killed and several injured in a shooting in the city on Wednesday, which including the targeting of a synagogue.
Footage from the attack was livestreamed on Amazon's video gaming platform Twitch, according to a Twitch spokeswoman.
The spokeswoman said the company "worked with urgency" to remove the content.
Shortly after the incident, which happened on the Jewish holy day of Yom Kippur, police said one person had been arrested, but they could not confirm to Euronews it was a shooter. They are still hunting for suspects.
The country's public prosecutor general responsibilities include crimes against the state, including terrorism, treason and espionage.
Interior Minister Horst Seehofer said: "Based on current information, we have to assume that it was at least an anti-Semitic attack. According to the federal prosecutors' office, there are enough indications that it was possibly a right-wing extremist motive. They have taken over the investigations."
"That on the Day of Atonement a synagogue was shot at hits us in the heart," said Germany's foreign minister Heiko Maas on Twitter:
"We must all act against anti-Semitism in our country."
The railway station in Halle, a city of 240,000, was closed down as a precaution amid the police operation.
A police spokeswoman told Euronews that there are at least two crime scenes.
The Associated Press cited a person interviewed on n-tv television as saying he had been in a kebab shop when he saw a man with a helmet and a military jacket fire shots into the establishment.
Police said they were also investigating reports of shots fired in Landsberg, 15 kilometres (about 10 miles) from Halle, although they could not immediately confirm any details.
"This is terrible news from Halle and I hope very much that the police catch the perpetrator, or perpetrators, as quickly as possible," government spokesman Steffen Seibert said, interrupting a regular government news conference.
Chancellor Angela Merkel visited a Berlin synagogue on Wednesday evening.