Indonesian soldiers the cockpit voice recorder of AirAsia QZ8501 at Iskandar airbase in Pangkalan Bun, Central Kalimantan January 13, 2015. [Photo/Agencies]

JAKARTA, Indonesia - An AirAsia plane that crashed last month with 162 people on board was climbing at an abnormally high rate, then plunged and suddenly disappeared from radar, Indonesia's transport minister said Tuesday.

Ignasius Jonan told Parliament that radar data showed the Airbus A320 was climbing at about 6,000 feet a minute before it disappeared on Dec. 28.

"It is not normal to climb like that, it's very rare for commercial planes, which normally climb just 1,000 to 2,000 feet per minute," he said. "It can only be done by a fighter jet."

He said the plane then plunged toward the sea and disappeared from radar.

Jonan did not say what caused the plane to climb so rapidly.

In their last contact with air-traffic controllers, the pilots of AirAsia Flight 8501 asked to climb from 32,000 feet to 38,000 feet to avoid threatening clouds, but were denied permission because of heavy air traffic. Four minutes later, the plane disappeared. No distress signal was received.