British Airways will push back departure times for some flights Wednesday because of a lighting issue at Heathrow Airport.

“We are delaying flights that have not already departed at this stage and diverting some flights that are airborne and due to arrive at Heathrow shortly,” British Airways said on its website. The carrier said it will update customers as soon as there is further information from Heathrow Airport.

The airport said it’s expecting some disruption throughout the morning as engineering teams investigate a technical issue with the lighting for its runways.

Heathrow is working to resolve the issue as quickly as possible, a representative for the airport said in an emailed response to a Bloomberg News query. Passengers should check their flight status with airlines before traveling to the airport, according to the email.

Fliers experiencing delays took to Twitter, with at least two saying they were held up at John F. Kennedy airport due to the Heathrow problem.