MAINZ, Germany — Police in Germany evacuated several buildings in six cities on Tuesday after bomb threats were emailed to officials. After searching the buildings, police in at least four of the cities said they found nothing suspicious.

Officials in Kaiserslautern, Chemnitz, Rendsburg, Augsburg, Göttingen and Neunkirchen received bomb threats to their general email inboxes, police in each city told NBC News.

In Göttingen, officials searched the building and reopened the streets in the area around two hours later. The town hall remained closed for the day, police announced in a tweet.

The threat in the southwestern city of Kaiserslautern led to the evacuation of a 21-story high rise where more than 1,000 people work. Police searched the building but found nothing. Police said in a tweet they are investigating the email in coordination with the other cities that received threats.

In Augsburg in southern Germany the town hall and a nearby administration building where around 500 people work were both evacuated. Police later said that no suspicious items were found.

In Neunkirchen, also in the southwest of Germany, police evacuated several buildings belonging to the town hall complex, but found nothing after searching the buildings.

“It is possible that the threat emails in the different German cities have been sent by one person, but the investigation is ongoing,” a police spokesman told NBC News.

Federal authorities told NBC News that they are aware of the emails and are coordinating the exchange of information between the various police departments, which are responsible for investigating the threats.

The multi-story town hall building in the east German city of Chemnitz was also evacuated after a bomb threat was sent to the city's general email inbox, police told NBC News. Police were searching the building.

In the northern German city of Rendsburg the local town hall was also evacuated this morning after receiving an email, police said.

Bild daily cited one police force as saying the threat level was unchanged. In January, courts in three German cities received bomb threats but no explosions occurred.

Andy Eckardt reported from Mainz, Germany, Rachel Elbaum from London.