(CNN) - The Federal Aviation Administration has suspended two air traffic controllers over last week's collision of two aircraft over the Hudson River that killed nine people, a spokeswoman said.
A controller at New Jersey's Teterboro Airport handling the flight of a Piper airplane carrying three people "was involved in apparently inappropriate conversations on the telephone at the time of the accident," FAA spokeswoman Laura Brown said in a statement Thursday.
A source with knowledge of the investigation said the controller was on the phone with his girlfriend "after he cleared the pilot for takeoff; he was still on the phone at the time of the crash."
In addition, "the supervisor was not present in the building as required," Brown said.
"While we have no reason to believe at this time that these actions contributed to the accident, this kind of conduct is unacceptable, and we have placed the employees on administrative leave and have begun disciplinary proceedings," she said.
"These are serious violations of the FAA regulations," said Mary Schiavo, former inspector general for the Transportation Department.