WASHINGTON, March 11 (Xinhua) -- U.S. Federal Aviation Administration (FAA) on Monday said it will issue a Continued Airworthiness Notification for Boeing 737 Max 8 operators, pledging to take "immediate and appropriate" action if safety issue is identified.

The move came after pressure mounted for U.S. regulators to ground U.S.-based Boeing 737 Max 8 planes, two of which had crashed in recent months.

Flyers Rights, an airline consumer organization, said the crashes "should compel the FAA to ground all these aircraft until it is clear that its automated control problems have been fixed."

"If you fail to do so now and a third crash occurs, you will be responsible," the organization said in an open letter to the FAA Monday.

Ethiopian Airlines said Sunday one of its flights bound for Nairobi, Kenya had crashed, killing all 157 people aboard. A Lion Air flight crashed in October, 2018, killing all 189 people on board.

After the deadly crash on Sunday, authorities in China, Indonesia and Ethiopian Airlines have announced to ground the 737 Max 8 aircraft.