A “minor collision” between two aircraft occurred at Heathrow on Wednesday evening, an airport spokesperson has said.
Police cars and fire engines attended the scene, but no injuries have been reported.
A Heathrow spokesperson 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.”
The London Ambulance Service confirmed it had sent teams to the scene.
“We were called today at 8.06pm to reports of an incident at Heathrow airport,” it said.
“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.
“We attended a reception centre for passengers but nobody required treatment or needed to be taken to hospital.”
It is understood that the incident was caused by a Korean Air plane hitting the tail of an Icelandair plane with one of its wings.
Guardian journalist Dan Sabbagh, who was on one of the flights, tweeted: “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.”
He added that there was “no apparent danger” and that nobody onboard was hurt.
Mr Sabbagh later told Sky News that passengers were disembarking the Korean Air flight, which had been due to depart for Seoul at 7.35pm. “The atmosphere is calm, just a feeling of mild nuisance,” he said.
The cause of the collision is being investigated.
While it is understood there is currently no significant impact on departures or arrivals, passengers are advised to check with their airlines on the status of their flights.