The Federal Aviation Administration has launched an investigation into how two aircraft nearly collided Thursday at Reagan National Airport in Washington, D.C.

An audio recording of air traffic controllers posted on YouTube shows them frantically telling the pilots of the Southwest and JetBlue flights to "stop."

"JetBlue 1554 stop! 1554 stop!" an agitated controller exclaimed.

"2937 stop!" another controller called out.

"We stopped. We were cleared to cross Runway 4," the Southwest pilot responded.

Both planes came to a halt just a few hundreds feet from each other, WUSA 9 reported.

The FAA told CNN that both planes had been sent to the same runway.

"An air traffic controller instructed Southwest Airlines Flight 2937 to cross Runway 4 at Ronald Reagan Washington National Airport while JetBlue Flight 1554 was starting its takeoff roll on the same runway," said the FAA. 

The Southwest jet was told to continue across the runway to another runway where it took off for its scheduled flight to Orlando. 

The JetBlue flight was directed back to runway 4."Do you have room to get around the Southwest or even double back on Runway 4 full length?" the tower asked.

"Looks like we can make a left on Alpha, JetBlue 1554," the pilot responded.

It then took off for Boston. 

JetBlue said it "aborted" a takeoff because of another plane crossing the runway. 

"No injuries were reported, and the aircraft was inspected before ultimately taking off for Boston. Safety is JetBlue's first priority, and we will work closely with federal officials as this event is fully investigated," the company said in a statement.

"We are aware of the incident and are working with the FAA to fully understand the circumstances," Southwest Airlines told CNN.