Police said in a tweet that the suspects fled in a car, and soon after reported that one person had been arrested. They gave no information about that person or reasons why they thought the attack was carried out by multiple assailants.
Officers were out in force across Halle, a city of 240,000, hunting down more suspects and urging residents to stay at home or indoors. The railway station in Halle was closed as a precaution. Police gave no details about the target, or targets, of the attack but federal prosecutors, who handle cases involving suspected terrorism or national security, took over the investigation.
A video clip broadcast by regional public broadcaster MDR showed a man in a helmet and an olive-colored top getting out of a car and firing four shots from behind the vehicle from a long-barreled gun. It wasn't clear what he was shooting at.
Pictures from the scene showed a body lying in the street behind a police cordon. News agency dpa reported the body was lying opposite a synagogue, about 30 meters (yards) away. Wednesday is the Jewish holy day of Yom Kippur, when synagogues would be busy.
A witness interviewed on n-tv television said he had been in a kebab shop when a man with a helmet and a military jacket threw something that looked like a grenade, which bounced off the doorframe. Conrad Roessler said the man then shot into the shop at least once.
"All the customers next to me ran, of course I did too — I think there were five or six of us in there," Roessler said. "The man behind me probably died." "I hid in the toilet," he said. "The others looked for the back entrance. I didn't know if there was one. I locked myself quietly in this toilet, and wrote to my family that I love them, and waited for something to happen."
Police then came into the shop, he said. The head of Halle's Jewish community, Max Privorotzki, told news magazine Der Spiegel there were 70 or 80 people inside the synagogue and security outside when the shooting occurred.
Synagogues are often protected by police in Germany, and police in two other eastern cities, Dresden and Leipzig, stepped up security at synagogues there after the shooting in Halle. Police said shots were also fired in Landsberg, about 15 kilometers (nearly 10 miles) from Halle. It wasn't clear whether the two shootings Wednesday were related.
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. The European Parliament held a moment of silence at the start of its session Wednesday to mark the unfolding situation in Halle.
Moulson reported from Berlin.