Facebook "intentionally and knowingly" violated U.K. data privacy and anti-competition laws and urgently needs to be regulated and investigated, a scathing new report by British lawmakers said.

The final report issued Monday by the U.K.'s Digital, Culture, Media and Sport committee concluded an 18-month investigation into Facebook and other social media companies for their role in spreading "fake news" and disinformation. In the 108-page document, lawmakers called for the creation of an independent regulator for social media sites and a mandatory code of conduct that, if breached, could result in "large fines."

"Companies like Facebook should not be allowed to behave like 'digital gangsters' in the online world, considering themselves to be ahead of and beyond the law," the report said.

The committee accused Facebook CEO Mark Zuckerberg of showing "contempt" toward U.K. parliament for declining to testify in front of lawmakers. Zuckerberg appeared in front of U.S. and EU lawmakers to discuss the company's data collection practices last year but sent other company representatives to testify in Britain.

"Mark Zuckerberg continually fails to show the levels of leadership and personal responsibility that should be expected from someone who sits at the top of one of the world's biggest companies," Damian Collins, chair of the committee, said on the committee's website.

In a statement, Facebook said it made a "significant contribution" to the investigation, answering more than 700 questions with four senior executives providing evidence, adding it supports "effective privacy legislation."

"While we still have more to do, we are not the same company we were a year ago," Karim Palant, U.K. public policy manager at Facebook, said.