Story highlights "When you attack a country, it's an act of war," McCain said

McCain also has scheduled a hearing for next week on foreign cyberthreats

(CNN) Sen. John McCain said Friday that Russia's alleged meddling in the 2016 presidential election amounted to an "act of war."

The Arizona Republican, who is chairman of the Senate Armed Services Committee, also has scheduled a hearing for next week on foreign cyberthreats to the US, which will also focus on Russian cyberhacking, a committee aide told CNN earlier Friday.

McCain, who is one of Washington's most prominent foreign policy hardliners, has criticized the recent sanctions and expulsions announced by the Obama administration this week as insufficient and belated. He made his latest comments in Ukraine, a nation threatened by a resurgent Russia, after meeting with Ukrainian President Petro Poroshenko.

"When you attack a country, it's an act of war," McCain said of the recent hackings on Ukrainian TV, according to a transcript compiled by Reuters. "And so we have to make sure that there is a price to pay so that we can perhaps persuade Russians to stop this kind of attacks on our very fundamentals of democracy."

McCain has invited James Clapper, the Director of National Intelligence, Admiral Mike Rogers, Director of the National Security Agency, and Marcel Lettre, the Undersecretary of Defense for Intelligence, to next week's hearing, according to the aide.

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