A large fire at a nearby electrical substation is causing power outages, closing the famous airport all day Friday local time, with further disruptions predicted.

The London airport, which is one of the world’s busiest for international travel, said it expects “significant disruption over the coming days” and warned passengers not to come until it reopens.

London’s Heathrow Airport, one of the world’s busiest, announced a complete shutdown all day Friday due to a “significant power outage” as a result of a large fire nearby and warned that “significant disruptions” can be expected over the coming days.