OTTAWA -- A Canadian MP and his British counterpart are asking Facebook CEO Mark Zuckerberg to appear before an international committee they have formed to examine disinformation and fake news.

Bob Zimmer, a British Columbia Conservative who chairs the House of Commons committee on information, privacy and ethics, and Damian Collins, who heads a similar parliamentary committee in the United Kingdom, want Zuckerberg to appear Nov. 27 in London.

They say the hearing at Westminster will allow members of the two parliaments -- and possibly representatives from other countries -- to ask the social-media executive about digital policy, vulnerabilities in cyberspace and potential threats to their democracies.

Both committees have previously asked Zuckerberg to appear before their respective members to discuss the breach of personal information involving Cambridge Analytica and Facebook -- as well as subsequent breaches -- but he has not done so.

There is also troublesome evidence of online Russian interference in the 2016 U.S. presidential vote by means of advertisements on Facebook.

In their joint letter to Zuckerberg, dated Wednesday, Zimmer and Collins request a reply by Nov. 7.

Over the last year, the Canadian and British parliamentary committees have both sought evidence from a Facebook executive "with sufficient authority" to give an accurate account of recent problems, says the letter.

"You have chosen instead to send less senior representatives, and have not yourself appeared, despite having taken up invitations from the U.S. Congress and Senate, and the European Parliament," the letter says.

"We understand that it is not possible to make yourself available to all parliaments. However, we believe that your users in other countries need a line of accountability to your organization -- directly, via yourself.

"We would have thought that this responsibility is something that you would want to take up. We both plan to issue final reports on this issue by the end of this December, 2018. The hearing of your evidence is now overdue, and urgent."