Counterterrorism police are now probing the cause of an electricity substation power that starved London’s Heathrow Airport of power and caused it to close down on Friday, sparking travel chaos, The Times of London reported.

They are examining the possibility of sabotage. The Times reported that the presence of counterterrorism detectives is a precautionary measure, and there is not yet an indication of foul play. These police have expertise that will help to draw a swift conclusion.

There are fears of active Russian sabotage operations in the U.K. and elsewhere in Europe amid Moscow’s war in Ukraine. Russian agents have been linked to multiple incidents in recent years, including a warehouse fire in London.

Heathrow is one of the world’s busiest airports, transporting 83.9 million passengers in 2024 alone.

This is a developing news story and will be updated shortly.