Luton Airport outside London said it suspended flights through at least midday Wednesday after a parking garage collapsed because of a fire overnight.

The fire, which began on Tuesday evening, led to a “partial structural collapse” at Terminal Car Park 2, the airport operator said on its website. Luton is the fourth-largest airport serving London, operating flights for mostly discount airlines.

Firefighters were still battling the blaze early Wednesday, and the airport advised passengers to not head to the airport until further notice.

This is a developing story. Check back for updates.