LONDON — Ireland’s data regulator has launched an investigation of Facebook over a recent data breach that allowed hackers access 50 million accounts.

The Irish Data Protection Commission said Wednesday that it will look into whether the U.S. social media giant complied with European regulations that went into effect earlier this year covering data protection.

The commission said in a statement that it would examine whether Facebook put in place “appropriate technical and organizational measures to ensure the security and safeguarding of the personal data it processes.”

The commission said earlier this week the number of EU accounts potentially affected numbered less than 5 million.

Ireland, which is Facebook’s lead privacy regulator for Europe, is moving swiftly to investigate the U.S. tech company since the breach became public on Sept. 28.