Terror threat shuts down Germany's Rock am Ring festival on opening night

German authorities shut down a popular rock music festival and cleared out thousands of fans Friday night after receiving a "concrete" terrorist threat.

Not yet clear if festival with an expected 90,000 fans will resume

Visitors leave the music festival Rock am Ring outside the western town of Nuerburg, Germany, on Friday. It's not yet clear if the festival will resume on Saturday. (Thomas Frey/Dpa via Associated Press)

German authorities shut down a popular rock music festival and cleared out thousands of fans Friday night after receiving a "concrete" terrorist threat. 

Rhineland-Palatinate government spokesperson Joachim Winkler told the dpa news agency there were tips of a possible terrorist attack and that the Rock am Ring festival was shut down on its opening night as a precaution. 

The German band Rammstein was the Friday night headliner, but hadn't yet started playing. 

Organizer Marek Lieberberg told journalists at the scene that he hoped the annual three-day festival would be able to resume Saturday as planned, but that it was not yet clear. 

The festival grounds were clear by 9:30 p.m. local time, about a half hour after people were told that they were going to have to leave.

Visitors stream out of the festival on Friday after the festival was shut down. (Thomas Frey/Dpa via Associated Press)

"The public reacted fantastically," Lieberberg said. 

It wasn't immediately clear how many fans were in attendance, but some 90,000 were expected by the end of the weekend at the event outside the western town of Nuerburg. Overall, some 85 bands were scheduled to play on four stages with Germany's Toten Hosen highlighting Saturday's list and California's System of a Down playing Sunday.

Last year's festival was plagued by severe weather. More than 70 people were injured after lightning struck and parts of the festival were cancelled.

Security heightened post-Manchester

Following the recent attack in Manchester outside a concert, organizers had instituted strict security controls including body searches, while backpacks and bags were banned. Some 1,200 police were to be on hand for the event, in uniform and in plain clothes.

Venues around the world, including Toronto's Air Canada Centre and Winnipeg's MTS Centre, said they were increasing security in response to what happened in Manchester.

Germany has been on alert since a number of violent attacks last year, including the truck attack on a Berlin Christmas market that left 12 victims dead and dozens of others injured. The attack, carried out by a young Tunisian man who had been denied asylum in Germany, was claimed by ISIS.

With files from CBC News