SEOUL, March 14 (Xinhua) -- Two South Korean airlines, which are set to introduce Boeing 737 MAX 8 passenger jets later this year, decided to ground the planes until safety is secured, Yonhap news agency reported Thursday.

The country's biggest air carrier Korean Air was quoted as saying that it decided not to fly the Boeing 737 MAX 8 planes, which saw crashes in recent months, until their safety is secured.

The Korean Air originally planned to adopt the aircraft from May. It signed a contract with Boeing in 2015 to purchase 50 MAX 8 planes by 2025.

The country's low-cost carrier T'way Air also decided not to operate the planes until safety is secured. It originally planned to adopt four MAX 8 jets in the second half of this year.

The decisions came amid rising global concern over the safety of the Boeing 737 MAX 8 planes after two fatal crashes in five months.

The Boeing 737 MAX 8 plane of Ethiopian Airlines crashed shortly after taking off from Addis Ababa on Sunday, killing all 157 on board.

Another jet of the same model, flown by Indonesian budget carrier Lion Air, crashed in October last year killing all 189 passengers on board.

Another South Korean budget carrier Eastar Jet decided Tuesday to ground the MAX 8 jets to alleviate public concerns about the plane's safety.

The Eastar Jet was the only South Korean air carrier that owns Boeing 737 MAX 8 planes, with two of the models in its fleet.