(CNN) Cambridge Analytica whistleblower Christopher Wylie says the data the firm gathered from Facebook could have come from more than 87 million users and could be stored in Russia.

The number of Facebook users whose personal information was accessed by Cambridge Analytica "could be higher, absolutely," than the 87 million users acknowledged by Facebook, Wylie told NBC's Chuck Todd during a "Meet the Press" segment Sunday.

Wylie added that his lawyer has been contacted by US authorities, including congressional investigators and the Department of Justice, and says he plans to cooperate with them.

"We're just setting out dates that I can actually go and sit down and meet with the authorities," he said.

The former Cambridge Analytica employee said that "a lot of people" had access to the data and referenced a "genuine risk" that the harvested data could be stored in Russia.

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