Shots were fired at a building complex housing a hookah (or shisha) bar in the German city of Stuttgart on Saturday, police have said.

An unknown perpetrator shot at a window at the entrance to the building and at the window of the hookah bar, which was closed at the time.

Police said that one bullet pierced the window of the bar, while the other withstood the attack.

It is not known when the shooting took place. The damaged windows were discovered on Saturday afternoon by an employee of the bar, who alerted authorities.

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Nobody was injured as it's believed no one was in the building at the time of the shooting, a police spokesman for the state capital of Baden-Württemberg said.

Criminal police specialists, including a firearms expert from the state's criminal investigations office, have secured the evidence.

Motive unclear

So far, the motive for the shooting remains unclear. However, the incident has rattled nerves, coming so soon after the deadly Hanau shootings.

Read more: Germany prepares for reprisal attacks after Hanau shootings

On Wednesday evening, a 43-year-old German killed nine people of immigrant descent in Hanau, which lies 170 kilometers (105 miles) from Stuttgart.

The victims were targeted at a hookah bar and a nearby cafe. Shortly afterward, the gunman also shot dead his 72-year-old mother and then took his own life.

Investigators say the perpetrator had left a far-right manifesto and suffered from mental health problems.

mm/tj (AFP, dpa)

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