BRUSSELS - European Union and British lawmakers demanded on Tuesday that social media giant Facebook should clarify data breach following revelations that personal data was massively misused for political purposes.

"We've invited Mark Zuckerberg to the European Parliament. Facebook needs to clarify before the representatives of 500 million Europeans that personal data is not being used to manipulate democracy," European Parliament president Antonio Tajani tweeted.

Cambridge Analytica, a British consulting company, was accused of harvesting data of up to 50 million Facebook users without permission and using the data to help politicians including US President Donald Trump and the Brexit campaign.

"If true, manipulating our personal data is unacceptable and a threat to democracy," Tajani said.

"We are waiting for Facebook representatives to testify on transparency and the respect of EU rules on data protection," he added.

British lawmakers have also summoned Facebook CEO Zuckerberg to give oral evidence after "misleading to the Committee" occurred at a previous hearing.

In a letter to Zuckerberg, Damian Collins, chair of the influential Digital, Culture, Media and Sport committee (DCMS), said the answer of Facebook officials "consistently understated the risk" of user data being used without their consent and given "misleading" evidence to the parliament.

"It's now time to hear from a senior Facebook executive with the sufficient authority to give an accurate account of this catastrophic failure of process," Collins said.