BERLIN (Reuters) - Germany said on Wednesday it wanted Facebook to clarify the use of its data after reports that a UK-based political consultancy improperly accessed information on millions of Facebook users to build detailed profiles on American voters.

"The government ... demands clarification from Facebook on the accusations," a government spokeswoman told a regular government news conference. "If it is really correct that the personal data of 50 million users was so easily tapped and used for political purposes, then this is not acceptable."

Facebook has been rocked this week by a whistleblower who said that Cambridge Analytica, a British-based firm hired by Trump for his election campaign, had improperly accessed information on millions of Facebook users to build detailed profiles on American voters.

(Writing by Paul Carrel; Editing by Michelle Martin)