Companies including Airbus SE, Deutsche Telekom AG and Orange SA have written to European Union officials to support a plan that would make it harder for US cloud providers to earn the highest cybersecurity certification.

Nearly 20 companies said customers increasingly want their data stored in Europe, and want security standards to be harmonized across the bloc, according to a letter that was seen by Bloomberg. Getting the voluntary certification can be useful for landing contracts with large local customers and governments.

ENISA, the EU’s cybersecurity regulator, has been working on plans for stricter rules that would prevent foreign …