One of the United Kingdom’s largest airports suspended flights on Monday after high temperatures damaged a runway. Temperatures soared up to 37 degrees Celsius (about 99 degrees Fahrenheit) in some parts of the country.

London Luton Airport announced the situation via Twitter and updated its status when the airport resumed operations on Monday evening.

An “essential runway repair” was required “after high surface temperatures caused a small section to lift,” the airport said on Twitter.

Full operations resumed just after 6 p.m. in London.

Luton Airport’s announcement came hours after the Royal Air Force (RAF) paused all flights to and from Brize Norton, its biggest air base, in Oxfordshire after a report from Sky News suggested that the runway had “melted.”

The U.K. Ministry of Defence tweeted a statement on flights at Brize Norton on Monday afternoon.

“During this period of extreme temperature flight safety remains the RAF’s top priority, so aircraft are using alternative airfields in line with a long-established plan. This means there is no impact on RAF operations,” the statement said.

Meanwhile, both Network Rail and Transport for London (TfL) have advised passengers against travel on Monday and Tuesday, unless for “essential journeys,” because of the hot weather. Train speed restrictions have also been introduced to protect railway tracks.

On Friday, the U.K.’s Met Office issued its first ever “red” warning for extreme heat for Monday and Tuesday, with temperatures predicted to reach 40 degrees Celsius (104 degrees Fahrenheit) in some parts of the country.

The Luton Airport shutdown is the latest incident in a turbulent summer for UK travel that’s seen thousands of flights canceled, huge security queues and countless reports of delayed or lost baggage.

Last week, Heathrow Airport announced a 100,000 a day passenger cap until September 11 and asked airlines to stop selling tickets for travel this summer as it struggles to deal with high demand and staffing shortages.