LONDON (AP) — A senior Labour party official says leaks from a report on Russian interference in British politics raises serious questions about the security of next month’s election.

The Sunday Times says the report from Parliament’s intelligence committee concludes that Russian interference may have affected Britain’s 2016 Brexit referendum, though the impact was “unquantifiable.” The Times says the report discusses the impact of articles posted by Russian new sites that were widely disseminated on social media.

Emily Thornberry, Labour’s foreign affairs spokeswoman, told the newspaper that Prime Minister Boris Johnson must “clear up the confusion, spin and speculation around this ISC report by publishing it in full at the earliest opportunity.”

She says if the Conservative leader does not, “people will rightly continue to ask: what is he trying to hide from the British public and why?”