LAS VEGAS, United States, Oct. 19 (Xinhua) -- U.S. Democratic and Republican presidential nominees Hillary Clinton and Donald Trump sparred over Russia's alleged interference in the U.S. presidential election during the final presidential debate held here Wednesday night.

Citing conclusions from intelligence agencies, Clinton accused Russia of being behind data breaches at Democratic political organizations and trying to influence the 2016 U.S. presidential election.

"This is such an unprecedented situation. We've never had a foreign government trying to interfere in our election," Clinton said, adding that she found it "deeply disturbing."

Earlier this month, U.S. intelligence agencies issued a joint statement claiming that Russia was behind the recent hacking of emails from U.S. political organizations in an attempt to interfere in the U.S. presidential election.

Trump rejected the U.S. government's assertion that Russia has sought to influence the election.

In response to the U.S. accusation, Russian Deputy Foreign Minister Sergey Ryabkov said claims of "Russian hackers" are groundless and exploited in the U.S. presidential election campaign.

The accusations are just "dirty tricks" of the incumbent U.S. administration, lack evidence and are fabricated to "escalate an unprecedented anti-Russia hysteria," Ryabkov said in a statement earlier this month.

On Wednesday, Clinton also charged that Russian President Vladimir Putin was backing Trump because "he'd rather have a puppet as president."

Trump again denied having a relationship with Putin.

"I don't know Putin," Trump said. "He said nice things about me. If we got along well, that would be good."