A Facebook whistleblower is set to give evidence to British MPs on Monday after warning that the network was understaffed to deal with security threats from countries such as Iran. Frances Haugen said that she witnessed the Iranian government performing sabotage on other state actors during her work as part of Facebook’s counterespionage team. She said that her unit was so stretched that it could deal with only a third of identified cases of states using Facebook to spy on people and militaries of other countries, she told <i>The Sunday Times</i>. “It was just completely inappropriately staffed,” she said. Her team of six of seven people “handled the entire world”. Facebook told the newspaper that more than 200 people were involved in disrupting sophisticated ‘adversarial threats’. The claims are the latest she has made about the tech giant since releasing thousands of pages of internal research documents she secretly copied before leaving her job. She says that Facebook refused to change its products because executives elevate profits over safety. Facebook founder Mark Zuckerberg has rejected the claims made by Ms Haugen, saying her attacks on the company were "misrepresenting" the work it does. He said the company "cares deeply about issues like safety, well-being and mental health" and that Ms Haugen's recent evidence to a US congressional committee "just doesn't reflect the company we know". "At the heart of these accusations is this idea that we prioritise profit over safety and well-being. That's just not true," he added. Ms Haugen will face questions from MPs scrutinising the draft Online Safety Bill, as the Government works out how to regulate tech firms and social media. Damian Collins, the chairman of the committee, said: "Frances Haugen's evidence has so far strengthened the case for an independent regulator with the power to audit and inspect the big tech companies. "There needs to be greater transparency on the decisions companies like Facebook take when they trade off user safety for user engagement. We look forward to discussing these issues with Frances Haugen."