LONDON (AP) — A massive fire tore through a newly built parking garage at one of London’s international airports early Wednesday, and four firefighters and an airport employee were hospitalized for smoke inhalation.

All flights at Luton Airport were suspended until 3 p.m. U.K. time Wednesday, the airport said in a statement, and would-be passengers were asked to stay away because emergency crews were still on scene and access was restricted.

Luton, about 35 miles (56 kilometers) north of central London, is a hub for budget airlines such as easyJet, Ryanair and others.

In addition to the five people hospitalized, a sixth person was treated at the scene.

Video posted on social media and on British news outlets’ websites showed police and fire department vehicles gathered outside a multi-story parking structure where the top level was engulfed in flames.

The parking garage for Terminal 2 partially collapsed after the fire started around 9 p.m. Tuesday.

Russell Taylor, 41, an account director from Kinross in Scotland, saw the flames after flying in to Luton from Edinburgh. He told the PA news agency that he first saw a couple of fire engines with a car on fire on an upper level.

“A few minutes later most of the upper floor was alight, car alarms were going off with loud explosions from cars going up in flames,” he said. “The speed in which the fire took hold was incredible.”