A jet carrying 286 passengers slammed on its brakes and aborted take-off at New York's John F Kennedy Airport after another plane began taxiing towards the runway it was using, it has emerged.
Federal Aviation Administration spokeswoman Kathleen Bergen said Lufthansa Flight 411 was cleared for take-off and EgyptAir Flight 986 was instructed to stay behind a "hold line" 250 feet behind the runway, at 6.50pm local time on Monday.
The EgyptAir crossed the line but did not enter the runway, she said.
"When air traffic control saw that, it cancelled the take-off for Lufthansa," Ms Bergen said, adding that the Lufthansa plane stopped "a considerable distance" from the EgyptAir jet.
In radio recordings posted on the website LiveATC.net, a controller in the JFK tower is heard giving take-off clearance to the Lufthansa flight while another controller directs the EgyptAir plane.
"No! Whoa-whoa-whoa-whoa!" shouts someone in the tower as the EgyptAir plane crosses the hold-short line.
"Cancel take-off! Cancel takeoff plans!" a controller shouts to the Lufthansa jet.
The Lufthansa plane, an Airbus A340, slammed on its brakes and came to a stop, then taxied off the runway. The pilot told controllers he was worried his brakes may have overheated, so controllers sent a port authority crew to help check the plane's landing gear.
"That was quite a show. Thought it was going to be a short career," a pilot who witnessed the aborted take-off remarked on the radio.
The FAA was looking at "pilot deviation" because the EgyptAir plane, a Boeing 777, did not follow air traffic instructions.
"The pilot was instructed to turn on to another taxiway but did not," Ms Bergen said.
She said the FAA was investigating and would determine how close the two planes came.
EgyptAir officials said they had no knowledge of the close call.
The Lufthansa flight was heading to Munich, airline spokesman Martin Riecken said. After the take-off was halted, the captain returned to the gate for a maintenance check while the passengers remained on the plane. The fight departed about two hours later, Mr Riecken said. There were no reports of injuries.
The New York Post said the EgyptAir flight was bound for Cairo. It was not immediately known how many people it was carrying. It departed about 90 minutes later.
Ms Bergen said investigators would listen to air traffic communications and look at radar replay.
Aviation authorities are increasingly worried about the danger of runway collisions as planes get bigger and airports more congested.
In December a JetBlue plane took a wrong turn at Boston's Logan Airport and nearly taxied on to a runway where another plane was taking off.
The deadliest crash in aviation history was a runway collision. In 1977 a KLM Boeing 747 crashed into a Pan Am 747 on the same runway in Tenerife, in the Canary Islands, killing 583 people.