US ex-President George W. Bush said on Thursday that "there's pretty clear evidence that the Russians meddled" in the 2016 American presidential election, forcefully rebutting fellow Republican Donald Trump's denials of Moscow trying to affect the vote, CNBC reeported quoting AP.

"The reason he does is because of the demise of the Soviet Union troubles him. Therefore, much of his moves (are) to regain Soviet hegemony," Bush said of Putin.

Bush also stressed the need to back NATO and other alliances the U.S. has with the world.

Putin "is pushing, constantly pushing, probing weaknesses," the former president said. "That's why NATO is very important." 

"There's pretty clear evidence that the Russians meddled," Bush said at a talk in Abu Dhabi, the capital of the United Arab Emirates. "Whether they affected the outcome is another question."

Bush also said that "it's problematic that a foreign nation is involved in our election system. Our democracy is only as good as people trust the results."