Bernie Sanders calls for investigation into Michael Flynn's Russia links during Donald Trump's election campaign

Pressure is building for the President to explain why he knew about Michael Flynn’s calls to Russia for weeks without taking action

Democrats, and some Republicans, have called for the 'truth' (Getty Images)

Bernie Sanders has joined Democrats’ growing calls for an independent and transparent investigation into Michael Flynn’s contact with the Russian ambassador during the election campaign amid questions that other Donald Trump aides were involved.

The Vermont Senator and former Presidential candidate wrote on twitter that he would ask the Senate Intelligence Committee to "thoroughly investigate if Russia coordinated with Trump and his campaign".

Mr Sanders’ request comes the same week that Mr Flynn, the former national security adviser, was reportedly forced to resign after the press revealed that he had reassured the Russian ambassador last year that sanctions would be overturned, and that Mr Trump knew this for three weeks before taking action.

At a press conference about Russian sanctions, the House Intelligence Committee introduced a bipartisan bill to ensure that Russia does not receive any sanctions relief "until it earns it", said House Minority Whip Steny Hoyer.

Ranking Member Adam Schiff added that the act would ensure that the Trump administration could not unilaterally repeal the sanctions "in response to their pernicious behaviour in Ukraine and as well as their meddling in our election".

"I’m dismayed this step is even necessary," he said.

Senate Minority Leader Chuck Schumer said in a statement on Tuesday that he hoped Republicans would join the Democrats to condemn the Trump team for allegedly colluding with Russian operatives, as the "crisis here rises above party".

"General Flynn’s resignation is not the end of this story, it is merely the beginning,” he said to reporters. “It is not the last chapter in this saga, it is the first. His resignation raises more questions than it answers and the American people deserve to know the truth."

Very few Republicans have spoken against the President, except for Arizona Senator John McCain and South Carolina Senator Lindsey Graham, who warned that Republicans could be the next target if the government does not take action.

The New York Times also reported that Mr Trump’s aides and associates had frequent contact during the election campaign with Russian members of government and intelligence, as found by US intelligence and law enforcement agencies by obtaining bank records, travel documents, interviews and intercepting phone calls.

The agencies did not conclude that Mr Trump’s team colluded with Russia to hack the Democratic National Committee computers or to carry out what the FBI and CIA deemed its "campaign of influence", posting fake news and sabotaging Hillary Clinton.

The agencies did express concern, however, about Mr Trump’s frequent praise of Vladimir Putin and his public encouragement of the Russians to hack into Ms Clinton’s computer.

The expose did not identify which aides the intelligence agencies were concerned about, and how much of the communication related to business rather than politics.

Attorney General Jeff Sessions is one person in the spotlight as he sat on the same national security council as Mr Flynn during the campaign.

White House Press Secretary Sean Spicer told reporters on Tuesday, before the New York Times story broke, that he was not aware that any Trump aides had spoken to Russia during the campaign - but he had been clear that Mr Flynn spoke to the Russian ambassador during the transition period after the election.

He insisted Mr Flynn was fired due to an "erosion of trust", not because there was a legal issue.