The number of countries where Facebook founder and CEO Mark Zuckerberg can expect to freely move about could soon shrink if he again refuses a meeting with an international committee of lawmakers investigating election meddling.

Zuckerberg and Facebook COO Sheryl Sandberg were invited on February 15 to appear before a May meeting of the International Grand Committee on Disinformation and "Fake News" in Ottawa, Canada. Neither have responded.

Bob Zimmer, who is chair of the committee and a member of Canada's parliament, said Zuckerberg and Sandberg should consider the offer carefully.

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"If we get a no, then there are some tools that I have as Committee Chair to compel them," said Zimmer. "I've said it before that I'd be willing to subpoena Mark Zuckerberg to appear."

If that happens, Canada will be the second country to promise Zuckerberg an order to appear before parliament. After the International Grand Committee met for the first time in London last year -- a meeting Zuckerberg declined to attend -- the head of a British committee investigating disinformation told CBS News that if Zuckerberg ever steps foot in England he can expect a visit from authorities.

"If Mark Zuckerberg came to the U.K. we would serve a summons on him, and if he refused to accept that summons then we could start contempt proceedings against him," Damian Collins, the chair of the Digital, Culture, Media and Sport Committee in the U.K. Parliament, said in a February interview.

The International Grand Committee is a collection of legislators from eight nations who first banded together on November 27 after they were stymied in their efforts to question leading tech executives for their separate disinformation investigations. When Zuckerberg didn't show up at that November meeting, he was represented by an empty chair surrounded by angry elected officials.

In addition to Zuckerberg and Sandberg, the list of those who received invitations to appear at the committee's second meeting in Ottawa on May 28 includes Twitter CEO Jack Dorsey; the company's executive chairman Omid Kordestani; Snap CEO Evan Spiegel; Andrew Jassy, CEO of the cloud computing platform Amazon Web Services; Amazon CEO Jeff Bezos; Google CEO Sundar Pichai; Eric Schmidt, the former executive chairman of Google's parent company, Alphabet; Apple CEO Tim Cook; Apple's COO Jeff Williams; and WhatsApp cofounder Brian Acton.

Zimmer said that because those executives have not previously been summoned, they are not facing possible subpoenas.

"We'll have a little more patience with them, but I have some plans for Facebook if they choose to say no. My hope is they will see the light and show up," Zimmer said.

No one from the U.S. was at the first meeting, but that may change with the second. A spokesperson for Sen. Mark Warner, D-Virgina, indicated he might attend the gathering in May, and Zimmer said others have also received invitations.