(Reuters) — An executive order signed by President Donald Trump to crack down on illegal immigration will not undermine two data transfer agreements between the United States and the European Union, Washington wrote in a letter to allay European concerns.

An executive order signed by Mr. Trump on Jan. 25 aiming to toughen enforcement of U.S. immigration law rattled the European Union, as it appeared to suggest Europeans would not be given the same privacy protections as U.S. citizens.

The order directs U.S. agencies to "exclude persons who are not United States citizens or lawful permanent residents from the protections of the Privacy Act regarding personally identifiable information."

Securing equal treatment of EU citizens was key to agreeing the Umbrella Agreement, which protects law enforcement data shared between the United States and the EU.

And the EU-U.S. Privacy Shield — which makes possible about $260 billion of trade in digital services — was only clinched after Washington agreed to protect the data from excessive surveillance and misuse by companies.

In the first written confirmation since the executive order stoked uncertainty over trans-Atlantic data flows, the U.S. Department of Justice said the executive order did not affect either the Umbrella Agreement or the Privacy Shield.

"Section 14 of the Executive Order does not affect the privacy rights extended by the Judicial Redress Act to Europeans. Nor does Section 14 affect the commitments the United States has made under the DPPA (Umbrella Agreement) or the Privacy Shield," Bruce Swartz, deputy assistant attorney general, wrote to the European Commission in a letter seen by Reuters.

EU Justice Commissioner Vera Jourova, who will travel to the United States at the end of March, said she was "not worried" but remained vigilant.

The EU-U.S. Privacy Shield is used by almost 2,000 companies including Google Inc., Facebook Inc. and Microsoft Corp. to store data about EU citizens on U.S. servers.

Its predecessor was struck down in 2015 by the EU's top court for allowing U.S. agents unfettered access to Europeans' data, forcing an acceleration of difficult talks to find a replacement.