The European Union and the United States signed a deal Thursday aimed at protecting personal data exchanged as part of efforts to prevent or investigate terrorism and other criminal offences.
Data protection has been a touchy issue in trans-Atlantic relations, due in part to revelations in 2013 that Washington had carried out mass spying on citizens and politicians in privacy-conscious Europe.
The so-called Umbrella Agreement will govern the exchange of personal data - such as criminal records, names and addresses - between US and EU authorities. Negotiations on the deal started in early 2011.
The two sides called Thursday's signing a "major step forward in EU-US relations."
The agreement will "advance the full respect for fundamental rights whenever personal data is being transferred between us," said Dutch Justice Minister Ard van der Steur, who signed it on behalf of EU governments as his country holds the rotating EU presidency.
EU Justice Commissioner Vera Jourova and US Attorney General Loretta Lynch also took part in the signing ceremony, which took place during EU-US talks on justice and home affairs.
The "historic" agreement will "facilitate cooperation in the fight against crime, including terrorism," Jourova said.
It still requires ratification in the European Parliament, which has paid close attention to data protection safeguards in negotiations with Washington. EU lawmakers expressed concern last month about a separate EU-US deal on commercial trans-Atlantic data flows.
The Umbrella Agreement sets out limits on how data can be used and for how long it can be held, as well as ensuring that information is not passed to third countries or organizations without prior consent.
It also gives EU citizens the possibility of challenging the use of their data in US courts, after US President Barack Obama signed a law in February extending US privacy protections to European citizens.