American Airlines Group Inc. joined a growing number of carriers around the globe that have discovered improperly certified replacement parts sold by a London-based company on their aircraft.

American disclosed the finding to Bloomberg News late Thursday, hours after US federal aviation regulators issued a warning to airlines and other aviation-industry companies. The carrier didn’t immediately identify the type of parts it found on the planes.

“Through the work of internal audits as well as collaboration with our suppliers, we’ve identified the uncertified components on a small number of aircraft — each were immediately taken out of service for replacement,” a spokeswoman for the airline said. “We’ll continue working with our suppliers and coordinating closely with the FAA to ensure these parts are no longer in our supply or otherwise in use on our aircraft.”

In its notice, the Federal Aviation Administration said the suspect parts were sold with allegedly forged airworthiness documents by AOG Technics Ltd. and used on a number of jets.

Read More: Bogus Jet-Engine Parts Fallout Spreads as FAA Warns Airlines

Discovery of the parts, first in Europe, has triggered a worldwide search. As many as 96 engines made by CFM International Inc., a joint venture of General Electric Co. and Safran SA, were fitted with the components. CFM makes engines for many older generation Airbus SE A320 and Boeing Co. 737 aircraft.

Southwest Airlines Co. earlier discovered engine blades linked to AOG, while United Airlines Holdings Inc. discovered parts that help direct air flow through engines.