Facebook could face a fine of over $1.6bn (£1.3bn) after a glitch exposed the personal photos of almost 7 million users.

The Irish Data Protection Commission (IDPC) said it had opened an inquiry into the security breach, which included images that users had never actually shared on the social network.

Under EU data laws, it could result in a fine equal to four per cent of Facebook's annual revenue if regulators determine the company did not do enough to prevent it.

A spokesman for the IDPC said: "We have this week commenced a statutory inquiry examining Facebook's compliance with the relevant provisions of the GDPR [General Data Protection Regulation].

The inquiry will also encompass another security breach announced in October that gave hackers total control of 30m users' accounts.

It is the latest in a litany of privacy issues involving the company this year which started with the Cambridge Analytica scandal in March.

"We're sorry this happened," said Tomer Bar, an engineering director at Facebook, in an official blog post, adding that the company would work to find out who was affected and to delete their photos from other companies' systems.

He also urged users to log in to any apps that they might have shared their Facebook photos with, in order to see what images they have access to.