Fans lining up for the Rock am Ring festival in Nuerburg were asked to take shelter as a precautionary measure on Friday when police were alerted to a possible terror threat, reported Digital Spy.
"Due to a terrorist threat the police have advised us to interrupt the festival," organisers said.
Rock am Ring has been held semi-annually since the mid 1980s and remains one of Germany's largest open air musical festivals, often attracting more than 100,000 people.
This year's lineup included Macklemore & Ryan Lewis, Bastille, System Of A Down, Prophets of Rage, Rag'n'Bone Man and German punk icons Die Toten Hosen.