Trump signed earlier this week an executive order on public security that eliminated privacy safeguards for foreigners.

It noted that "agencies shall, to the extent consistent with applicable law, ensure that their privacy policies exclude persons who are not United States citizens."

Trump’s move sparked concerns that Privacy Shield, a recent EU-US data-sharing treaty, would no longer be fit to protect EU nationals’ information in the hands of US firms.

Jourova shed doubt on whether Trump's executive order would survive.

"There are basic principles which set the limits for the national security bodies for the access to the data," she said.

Jourova plans on meeting with her US counterparts, including Trump's secretary of commerce, Wilbur Ross, a 79-year old Wall Street multibillionaire. She also wants to discuss the issue with the new US attorney general, Jeff Sessions.

"I need to have reconfirmation that there is continuity and we will be very strict assessors of the current decisions because Privacy Shield is not a one-off decision, it is the mechanism where we have several American national authorities involved," said Jourova.

An annual report on how the agreement works in practice is set to be published in September.

Some 1,500 companies have signed up to the Shield over the past six months, including US technology giants Apple, Google, and Microsoft.

The Shield was put in place after the European Court of Justice scrapped a previous accord, called Safe Harbour, amid revelations of mass-scale US snooping in the EU.

The European Commission, in an emailed statement, had on Thursday said Trump's executive order would not change much because US Privacy Act never offered much protection in the first place.

"We are aware of the executive order on public safety. The US Privacy Act has never offered data protection rights to Europeans," a commission spokesperson had said in an email.

The commission added on Thursday that a separate data treaty, the so-called EU-US Umbrella Agreement, would also stay in place.

Set for launch in early February, the Umbrella accord governs privacy rights of EU nationals in EU-US police cooperation.

"To finalise this agreement the US Congress adopted a new law last year, the US Judicial Redress Act, which extends the benefits of the US Privacy Act to Europeans and gives them access to US courts," said the spokesperson.

Not everyone is convinced that the US will follow through on its commitments.

A Dutch liberal MEP, Sophie in‘t Veld, has said the chances of the Umbrella agreement being enacted in full by the US was "almost nil".

Edward Snowden, a former US intelligence contractor, who lifted the lid on US snooping in the EU, also said last September that Privacy Shield would not stop US services from poking around in Europeans’ private lives.