The U.S. Federal Aviation Administration is investigating whether false or incorrect documents were used to verify the authenticity of titanium used in some recently manufactured Boeing jets, the agency said.

The New York Times, which first reported the issue on Friday, said the FAA is also investigating the authenticity of documents for titanium used in some Airbus jets.

Aircraft manufacturers are facing strong demand for new planes due to a surge in post-pandemic travel. However, supply-chain problems and component shortages are limiting their ability to meet this demand.

Titanium is an important component in the aerospace supply chain and is used to make landing gears, blades and turbine discs for aircraft.

The FAA said Boeing reported a voluntary disclosure “regarding procurement of material through a distributor who may have falsified or provided incorrect records.”

The agency added, “Boeing issued a bulletin outlining ways suppliers should remain alert to the potential of falsified records.”

Boeing said the issue involves the broader industry and some titanium shipments received by a limited set of suppliers, affecting a small number of airplane parts.

The planemaker said it was removing any such parts from airplanes prior to delivery and added there is no impact to safety.

Airbus said it was aware of the reports but said “numerous tests have been performed on parts coming from the same source of supply. They show that the A220’s airworthiness remains intact.”