John McCain
John McCainReuters

Russian President Vladimir Putin is a bigger threat to world security than the Islamic State (ISIS) group, Senator John McCain opined on Monday.

Speaking in an interview with the Australian Broadcasting Corporation during a visit to Canberra, McCain said Putin was the "premier and most important threat, more so than ISIS".

"I think ISIS can do terrible things. But it's the Russians who tried to destroy the fundamental of democracy and that is to change the outcome of an American election," he said.

"I've seen no evidence they succeeded, but they tried and they are still trying to change elections,” continued McCain.

"They just tried to affect the outcome of the French election. So I view Vladimir Putin — who has dismembered Ukraine, a sovereign nation, who is putting pressure on the Baltics — I view the Russians as the far greatest challenge that we have," said McCain, who added that the U.S. needed to respond to Russia with sanctions.

"We have done nothing since the election last November to respond to Vladimir Putin's attempt to change the outcome of our elections. So, way to go Vladimir. We haven't responded at all. Hopefully when we get back from recess the Senate will enact sanctions on Russia."

McCain has been a longtime critic of Putin and, in fact, was one of nine American officials sanctioned by Russia in 2014, a move that came in response to then-President Barack Obama sanctioning top Russian officials.

Also in 2014, McCain compared the actions of Putin in Crimea to actions taken by Adolf Hitler.