A gang of up to 50 teenagers have been accused of "causing chaos" and threatening staff in KFC and McDonald's in Consett in County Durham.
Police have said that large groups of teenagers, including both boys and girls, threw around food and threatened staff in the fast food restaurants.
Officers are now checking CCTV footage from both venues to identify those responsible for the disorder.
Last night, a spokesman for Consett Police posted a warning to parents on Facebook saying:
"Over the last few nights large groups of up to 50 teenagers, males and females have caused chaos in McDonald's Consett and KFC.
"They have threatened staff in both fast food restaurants, throwing food around and causing anti-social behaviour."
"Banning letters will be issued and some will be receiving a visit by police."