A driver plowed through a crowded pedestrian zone on Monday afternoon in central Leipzig, in eastern Germany, killing at least two people and severely injuring two others, according to the police.

The state interior minister, Armin Schuster, said that the police had arrested the driver, a 33-year-old German-born man who lived nearby. The authorities believe he acted alone and view the event as an intentional “rampage,” Mr. Schuster said at a press briefing on Monday evening that he gave with other senior officials.

The officials did not comment on the man’s motive or mental state, but Mr. Schuster said that his “emotional instability” could have played a role. The driver is being investigated for several counts of murder and attempted murder, Claudia Laube, Leipzig’s public attorney, said at the briefing.

There have been several vehicle attacks in Germany in recent years in which assailants drove into crowds. The deadliest of these occurred in Magdeburg, in eastern Germany, in December 2024, when a driver plowed through a Christmas market, killing six people and injuring 309 others.

In the incident on Monday in Leipzig, the driver turned off a major square in the city center, the Augustusplatz, and then sped down a lively pedestrian-only shopping street, according to the police. The two people killed were hit in separate collisions, the police said. Helicopters were used to bring some of the victims to the hospital.

Ruzhdi Korça, 53, a roof inspector from Kosovo, said he was on a work trip to Leipzig and had witnessed part of the attack as he ate ice cream nearby.

“Suddenly I heard the screaming from the people nearby me,” he said. Some of them began “running away, trying to escape from this crazy driver,” he said.

As the car sped past, Mr. Korça said, he saw a young man on top of it, screaming. The driver was also screaming, Mr. Korça said. Then he heard a crash and more screaming, shortly before the police arrived and closed off the area, he said.

Burkhard Jung, Leipzig’s mayor, said at a hastily called news briefing that it was “really almost unbearable to witness such an act on a Monday afternoon in the city center.” Mr. Jung said the events had set off “a day of deep mourning for our city.”

It remains unclear how — or if — the driver circumvented the pollards that protect most German pedestrian-only city centers from just such attacks, the police said on Monday night.

By Monday evening, the entire street had been closed off, with its shops and restaurants closed early.