Britain’s Telegraph newspaper reported that the cyber attack that caused major disruption to Royal Mail’s international export services was caused by Lockbit, a ransomware group that some cyber security experts believe has members based in Russia.

Royal Mail, one of the world’s largest postal and parcel companies serving thousands of businesses, was still unable to deliver to overseas destinations on Thursday, according to an update on its website following the incident it reported on Wednesday.

To prevent a build-up of export shipments on its network, the British postal company, which is part of International Distributions Services IDSI.L, advised customers not to send international export shipments until further notice.

Royal Mail, which declined to comment on the Telegraph’s report, previously said it had hired external experts and notified security authorities as it investigated the incident.

The UK Information Commissioner’s Office said it would investigate, while the National Cyber ​​Security Center said it was working with the company and the National Organized Crime Agency to “fully understand the impact”.

Lockbit, whose members some cyber security experts say are based in Russia, also claimed to have attacked a French cosmetics firm called Nuxe, Le Parisien newspaper reported on Thursday.