The Federal Aviation Administration (FAA) released a statement Sunday saying Boeing has informed them that some parts for the company's grounded 737 Max passenger plane, and prior model 737 Next Generation (NG), may have been improperly manufactured. Boeing said the part known as a leading-edge slat track — a mechanism that modifies the lift and drag characteristics of the plane's wing during takeoffs and landings — is among 148 parts from a Boeing supplier that are under concern.

According to the FAA, 32 Boeing NG and 33 Boeing Max aircraft are affected in the U.S., with the number increasing to 133 NG and 179 Max worldwide.

In its statement, the FAA said, "The affected parts may be susceptible to premature failure or cracks resulting from the improper manufacturing process. Although a complete failure of a leading-edge slat track would not result in the loss of the aircraft, a risk remains that a failed part could lead to aircraft damage in flight."

The Boeing 737 Next Generation airplane seen in an undated photo provided by Boeing. Boeing

The FAA is issuing an Airworthiness Directive to mandate Boeing's service actions to identify and remove the discrepant parts from service, estimating that "up to 148 parts manufactured by a Boeing sub-tier supplier are affected."

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In response, Boeing told CBS News they are working with the FAA and have "contacted 737 operators advising them to inspect the slat track assemblies on certain airplanes. One batch of slat tracks with specific lot numbers produced by a supplier was found to have a potential nonconformance."

"We are committed to supporting our customers in every way possible as they identify and replace these potentially non-conforming tracks," said Kevin McAllister, president & CEO of Boeing Commercial Airplanes. Boeing confirmed that it has not been informed of any "in-service issues related to this batch of slat tracks."

Boeing has faced increased scrutiny since two crashes of Boeing 737 Max planes killed 346 people. In October 2018, Lion Air Flight 610 crashed 12 minutes after takeoff, killing all 189 people on board. In March of this year, Ethiopian Airlines Flight 302 crashed into the ground six minutes after takeoff, killing 157 people. In response, all Boeing 737 Max planes were grounded worldwide.

On Wednesday, Boeing CEO Dennis Muilenburg told "CBS Evening News" incoming anchor Norah O'Donnell, "We can't change what has happened in these accidents but we can be absolutely resolute in what we're going to do on safety going forward."

Kathryn Krupnik contributed to this report.