Preliminary data from the Indonesian authorities:
When the Boeing 737-800 maintained FL340, the air traffic controller instructed to climb to FL360. After passed FL342, the TCAS TA activated followed by RA with aural warning DON’T CLIMB. The intruder traffic was an Airbus A320-200 aircraft which was maintaining FL350 from the opposite direction. The Boeing 737-800 pilot followed the RA until clear of conflict.