The Malaysian transport minister has vowed to take action against an air traffic control supervisor if it is confirmed that he was sleeping on the job when Malaysia Airlines Flight 370 disappeared a year ago.

An interim investigation report last Sunday published transcripts of conversation between an airline official and a Kuala Lumpur air traffic controller. Nearly four hours after the Boeing 777 with 239 people aboard dropped off radar while flying from Kuala Lumpur to Beijing on March 8, 2014, the controller had said he would need to wake up his supervisor to confirm details of the plane's location.

Transport Minister Liow Tiong Lai said Thursday that his department is conducting an internal probe and that action would be taken if there was any misconduct.