Writing in the Financial Times, US Commerce Secretary Wilbur Ross insisted GDPR "could significantly interrupt transatlantic co-operation and create unnecessary barriers to trade, not only for the US, but for everyone outside the EU".
He added that US companies and government agencies are worried about being fined by the EU if they "accidentally" break the rules, adding that GDPR could disrupt initiatives working on "financial regulation, medical research, emergency management co-ordination, and important commerce".
Ross added: "Pharmaceutical companies may not be able to submit medical data from drug trials involving European patients to US authorities, which could delay the approval of new life-saving drugs."
He also expressed concerns about identifying online criminals: "That could stop law enforcement from ascertaining who is behind websites that propagate terrorist information, sponsor malicious botnets or steal IP addresses."
Ross' comments follow reports that leading US news websites, including the NY Daily News, the Chicago Tribune and Los Angeles Times – have blocked EU users since GDPR D-Day on May 25.
Readers have been greeted with the message: "Unfortunately, our website is currently unavailable in most European countries. We are engaged on the issue and committed to looking at options that support our full range of digital offerings to the EU market. We continue to identify technical compliance solutions that will provide all readers with our award-winning journalism."