The European Parliament on Tuesday invited Facebook chief Mark Zuckerberg to speak following revelations that a firm working for Donald Trump's US presidential campaign harvested data on 50 million users.
The parliament and the European Commission, the 28-nation EU executive, have already called for an urgent investigation into the scandal.
"We've invited Mark Zuckerberg to the European Parliament," its President Antonio Tajani tweeted.
"Facebook needs to clarify before the representatives of 500 million Europeans that personal data is not being used to manipulate democracy."
Facebook has faced worldwide criticism over the claims that Cambridge Analytica, the UK data analysis firm hired by Trump's 2016 campaign, harvested and misused data on 50 million members.
The European Parliament's Brexit coordinator Guy Verhofstadt, a Belgian former prime minister, also called on the Facebook chief to personally answer the criticisms.
"When is Mark Zuckerberg going to explain what happened with our data? The data breach is an absolute scandal," tweeted Verhofstadt, who heads the parliament's liberal group.
"The European Parliament must start an investigation."
The EU parliament's civil liberties committee on Monday sent a letter to Facebook asking it to testify before the body, a parliamentary spokesperson told AFP.
British lawmakers on Monday also asked Zuckerberg to give evidence to a UK parliamentary committee on the data row.
EU Justice Commissioner Vera Jourova, who has called the breach "horrifying", was seeking to meet with Facebook during her visit this week to Washington.
Her office said she had also called on independent European data protection authorities who are meeting Tuesday in Brussels to probe the growing Facebook scandal.
"Commissioner Jourova would encourage setting up a taskforce to investigate this case," as the authorities did last year with a similar breach by cab firm Uber, her office said.
Britain's Information Commissioner Elizabeth Denham has already said her office would seek a court warrant on Tuesday to search Cambridge Analytica's computer servers.
Britain has voted to leave the EU but remains a member state until next year.
EU digital commissioner Mariya Gabriel told a press conference on Tuesday "we are constantly following this case as it unfolds."
Gabriel added that the EU will say "loud and clear" that "the protection of personal data is a core value for the European Union."