The European Commission on Monday sought to play down the impact of a cyberattack on parts of its public web infrastructure, saying there was no evidence its internal systems had been compromised.

In a statement issued Friday, the Commission said it had detected an incident affecting the Europa.eu web portal, the European Union’s central online platform hosting websites and services for its institutions.

The hacking group known as ShinyHunters has claimed responsibility, alleging it stole more than 350 gigabytes of data, including databases, emails and internal documents, and has published samples on its dark web leak site.

Speaking to reporters on Monday, Commission spokesperson Thomas Regnier confirmed some elements of the claims, including that parts of the Europa platform are hosted on cloud infrastructure provided by Amazon, but sought to minimize the significance of the breach.

Regnier said the Commission’s defense systems “immediately detected the malicious activities” and contained the incident, adding that “risk mitigation measures were implemented by our services to protect our services and data without disrupting the availability of our European websites.”

He stressed that the affected domains were limited to Europa.eu public websites and that the Commission’s “internal infrastructure has absolutely not been affected.”

“We’re talking about data that is potentially already in the public domain,” Regnier said.

The Commission did not specify what data may have been accessed or how many users could be affected, and declined to comment on whether personal data was involved.

Regnier declined to provide further details, citing the ongoing investigation. The Commission said it is working with cybersecurity experts and relevant authorities to assess the scope of the breach and notify any affected parties.

ShinyHunters is a well-known cybercrime group that has claimed multiple breaches in recent years, sometimes allegedly using historical datasets in its extortion attempts. Members of the group were previously accused of launching hacking campaigns against various industries last summer before a spate of arrests slowed them down.