Two planes have been involved in a "minor collision" on the tarmac at Heathrow.
An Icelandair aircraft and Korean Air jet were involved in the incident at around 8pm on Wednesday.
Emergency services rushed to the scene but no injuries have been reported.
A spokeswoman for Heathrow said: "Emergency services are attending an incident involving two aircraft on the airfield.
"No injuries have been reported but emergency services are attending to ensure all passengers and crew are safe and well."
London Fire Brigade attended the scene, alongside the London Ambulance Service (LAS).
"We sent a number of resources to the scene including members of our Hazardous Area Response Team (HART), a clinical team leader, a cycle responder and an incident response officer," a LAS spokesman said.
"We attended a reception centre for passengers but nobody required treatment or needed to be taken to hospital."
The incident remains under investigation. There are currently no significant impacts to departures or arrivals but passengers have been urged to check with their airlines.
Passengers took to Twitter to share images of emergency vehicles with blue flashing lights on the runway.
Dan Sabbagh, a Guardian journalist, was aboard one of the planes and tweeted: "Was on this plane but can't say we felt anything from the inside. No apparent danger, nobody hurt".
He added: "I'm on Korean Air plane that clipped an Icelandair plane at Heathrow - a passenger on the other side saw the incident told me the wing of our plane damaged the others' tail."
Steve Smith uploaded a video, asking: "Is this normal for Heathrow? Got to be four or five different emergency service vehicles with blue lights flashing on the tarmac."
A user called Richard replied: "I was watching out the window while we taxied and I'm pretty sure we scraped another with our wing tip."
He later added: "We have been told that we are going back to the gate due to a technical issue.
"But that was 15 mins ago and we haven't moved."
