The New York Stock Exchange is considering proceeding with delisting three major Chinese telecommunications firms after Treasury Secretary Steven Mnuchin criticized its shock decision to grant the companies a reprieve, said three people familiar with the matter.

The NYSE’s potential pivot follows a whirlwind 18 hours in which the exchange caught U.S. officials off guard, with the exasperation reaching the highest levels of the Trump administration. The back-and-forth also sowed deep confusion within global financial markets about the policy that set off the remarkable chain of events: an order signed by President Donald Trump in November that requires investors to unload Chinese businesses deemed a threat to U.S. national security.

Mnuchin entered the fray Tuesday, calling NYSE Group Inc. President Stacey Cunningham to express his displeasure with the exchange’s decision to let China Mobile Ltd., China Telecom Corp. and China Unicom Hong Kong Ltd. keep trading on the Big Board, said the people who asked not to be named in discussing a private conversation. Also involved in the administration’s response were Chief of Staff Mark Meadows, National Security Adviser Robert O’Brien and National Economic Council Director Larry Kudlow.