JAKARTA, Oct. 15 (Xinhua) -- The Indonesian Transportation Ministry grounded three Boeing 737NG (Next Generation) planes operated by two airlines following the findings of cracks in the aircraft, an official said on Tuesday.

The three grounded planes included one operated by state-run airlines Garuda Indonesia and two by private airlines Sriwijaya Air, said Airworthiness and Plane Operation Director at the ministry Avirianto.

Grounding of those planes would continue until further recommendations were issued by Boeing, he said.

"Furthermore we advise all national airlines operating Boeing 737NG including Garuda Indonesia, Lion Air, Batik Air and Sriwijaya Air to periodically conduct maintenance program every 3,500 Flight Cycle Number (FCN) that suits with Directorate General of Civil Aviation (DGCA) mechanism," he said.

Cracks in those planes were found in the ones which already had 30,000 FCN, he said.

The cracks were found in one of three Boeing 737NG operated by Garuda Indonesia, while in Sriwijaya Air cracks were found in two of five planes of the same type.

The grounding order was issued after inspections carried out by the ministry to follow suit airworthiness directives issued by international aviation agencies to check the Boeing 737NG planes operated by all airlines in the world.

Indonesia has banned operation of Boeing 737 Max 8 plane after a deadly crash of Lion Air flight on Oct. 29 last year that killed all 189 people aboard.