BRUSSELS - US House Judiciary Chair Jim Jordan on Sunday demanded EU antitrust chief Teresa Ribera clarify how she enforces the European Union (EU)'s rules reining in Big Tech, saying they appear to target US companies.

The request came two days after US President Donald Trump signed a memorandum warning that his administration would scrutinize the EU's Digital Markets Act and the Digital Services Act "that dictate how American companies interact with consumers in the European Union".

The Digital Markets Act sets out a list of dos and don'ts for Alphabet, Amazon, Apple, Booking.com, Meta Platforms, Microsoft, aimed at securing a level playing field and giving consumers more choices.

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"We write to express our concerns that the DMA may target American companies," Jordan wrote in a letter sent to Ribera on Sunday and seen by Reuters, saying that the rules subject companies to burdensome regulations and give European companies an advantage.

Scott Fitzgerald, chairman of the subcommittee on the administrative state, regulatory reform and antitrust, was a co-signatory to the letter.

The letter criticized fines up to 10 percent of global annual revenues for DMA violations.

"These severe fines appear to have two goals: to compel businesses to follow European standards worldwide, and as a European tax on American companies," Jordan and Fitzgerald said.

"These, along with other provisions of the DMA, stifle innovation, disincentivize research and development, and hand vast amounts of highly valuable proprietary data to companies and adversarial nations," the letter said.

The two urged Ribera to brief the judiciary committee by March 10.

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The European Commission did not respond to a request for comment on Sunday.

The European Commission, where Ribera is the second most powerful official after its president, Ursula von der Leyen, has denied taking aim at American companies.

Ribera in an interview with Reuters last Monday said the EU executive should not be pushed into making changes to laws that have been approved by lawmakers.