Donald Trump has been accused of issuing “very dangerous” statement on the investigation into alleged Russian hacking during the 2016 election campaign, according to the America's former ambassador to Moscow.

Michael McFaul said the US leader was being "very scary" after he tweeted about allegations of Russian interference in the US presidential election, ahead of Intelligence chiefs giving evidence to Congress on the matter.

The President has been dogged by allegations that his campaign team had links to Russian officials.

In January, US intelligence agencies said Kremlin-backed hackers had broken into the email accounts of senior Democrats and released embarrassing ones in order to help Mr Trump defeat Hillary Clinton.

CNN uses screenshot form Fallout 4 to explain how bad Russian hacking

A report by the CIA, FBI and National Security Agency (NSA) said Russian leader Vladimir Putin "ordered" a campaign aimed at influencing the election.

Before FBI director James Comey and NSA chief Admiral Mike Rogers could give evidence at a rare open hearing of the congressional intelligence committee, Mr Trump took to Twitter to denounce the accusations.

“The Democrats made up and pushed the Russian story as an excuse for running a terrible campaign,” the President said. “Big advantage in Electoral College and lost!”

His statement was denounced by Mr McFaul, who served as US ambassador in Russia from 2012 to 2014.

Retweeting the President, Mr McFaul said: “This statement is very dangerous. Means that Trump will do absolutely nothing to make changes to protect the integrity of future elections.”

He added: “The Russians attacked us last year. They violated our sovereignty. Meddled in our elections. And our president denies it. Very scary.”

Mr McFaul added that Mr Trump's tweets were "scary" because he is the "Commander in Chief, not a crazy uncle at Thanksgiving".

The President has repeatedly shrugged off claims that Moscow-backed hackers accessed and leaked Democratic Party emails during last year’s election, in order to sway the result in Mr Trump’s favour.