Investing.com -- The European Commission experienced a cyberattack on Tuesday that may have resulted in the theft of internal data, according to a commission spokesman.

The breach affected the commission's Amazon Web Services account before being detected and blocked, spokesman Thomas Regnier said. An internal investigation is underway to determine the extent of the breach.

"I can confirm that the commission discovered a cyber-attack, which affected part of our cloud infrastructure," Regnier said. "The commission's internal systems were not affected by the cyber-attack."

Cybersecurity blog Bleeping Computer first reported the incident and said the person responsible for the hack claimed to have stolen more than 350 gigabytes of data.

The attack follows a separate security incident affecting a high-ranking commission official earlier this month. Someone uploaded an intercepted WhatsApp call between the official and a Politico journalist onto YouTube. Both Politico and the commission said their devices and networks showed no evidence of being compromised.