US president-elect Donald Trump said yesterday a report that the CIA concluded that Russia intervened in the US presidential election to boost his candidacy is "ridiculous."

He said the claim is as excuse by Democrats to explain his upset victory over Hillary Clinton.

"Every week it's another excuse," Trump said in an interview with Fox News.

"Nobody really knows, and hacking is very interesting. Once they hack, if you don't catch them in the act, you're not going to catch them," he said. "They have no idea if it's Russia or China or somebody. It could be somebody sitting in a bed some place."

Trump's comments came in response to a Washington Post report saying the CIA concluded in a secret assessment that Russia's goal was to help Trump win. The newspaper quoted unidentified sources who had been briefed on the matter as saying Russia wanted to boost Trump not just undermine confidence in the US electoral system.

Intelligence agencies have identified individuals with connections to the Russian government who provided the whistleblowing website WikiLeaks with hacked emails from the Democratic National Committee and others, including Clinton campaign chairperson John Podesta, the Post said.

Earlier yesterday, four US senators said they were committed to conducting a bipartisan review of what the White House called "malicious cyber activity" during the campaign.

Congress has worked to address the challenge of cybersecurity, "but recent events show that more must be done," the four senators said.

The statement issued jointly by Republican senators John McCain and Lindsey Graham and Democrats Charles Schumer and Jack Reed follows President Barack Obama's order of an intelligence review of incidents of cyberhacking during the election.

US intelligence agencies in October accused Russia of intentionally interfering with the presidential election process by directing attacks on email systems. Russia said the claims were unproven.

The senators' statement said reports of Russian interference in the US presidential election "should alarm every American".

Reince Priebus, who has been named to serve as White House chief of staff after president-elect Trump takes office in January, reacted to the senators' statement by saying he supports anything that protects Americans from foreign interference.

"I'm all for finding out how in the world this stuff is happening and so that we can put systems in place to protect Americans. Again, we don't like this," Priebus said on ABC.

But Priebus also said it wouldn't change the outcome of the election even if an investigation were to definitively pin the hacks on Russia.

"Donald Trump won in an electoral landslide that had nothing to do with the Russians," Priebus said, adding that not all of the intelligence agencies agreed that Russia was the source of the interference.

He also denied a New York Times report that the Republican National Committee (RNC) also was hacked by Russians. The newspaper said US intelligence agencies based their conclusion that Russia's meddling was part of an effort to aid Trump on their finding that the RNC's computer systems was also hacked, but none of that information was released.

- dpa