US President Donald Trump is currently under intense pressure from leading members of the Republican Party who have joined the calls for a wide ranging investigations into Michael Flynn’s links with Russia.

Flynn, a close confidant of Trump and former US national security adviser, resigned on Monday over claims that he discussed US sanctions with Russia before Donald Trump took office.

On Tuesday, a White House spokesman said that President Trump knew weeks ago there were problems with the Russia phone calls.

The recent development came as the New York Times reported that phone records and intercepted calls show members of Trump’s presidential campaign, as well as other Trump associates, “had repeated contacts with senior Russian intelligence officials in the year before the election”.

However, officials spoken to by the newspaper said they had not yet seen evidence that the Trump campaign colluded with Russia on the hacking of the Democratic National Committee or to influence the election.

Both the Senate and House intelligence committees, as well as the FBI, are already examining Russian involvement in the election. It is not yet clear whether the latest claims will be included in their scope.

Flynn, a retired army lieutenant-general, initially denied having discussed sanctions with the Russian Ambassador, Sergei Kislyak, and Vice-President Mike Pence even denied the allegations on his behalf during a TV interview.

The US House Intelligence Committee Chairman, Devin Nunes told reporters on Tuesday he wanted to examine the leaks, and said the FBI should explain why Flynn’s conversation had been recorded.

But the Senate’s second-ranking Republican, John Cornyn, and other Republican senators have called for an investigation into Trump’s connections with Russian officials.

John McCain, Chairman of the Senate Armed Services Committee, said Flynn’s resignation was a “troubling indication of the dysfunction of the current national security apparatus”, which raised questions about Trump’s intentions towards Russia.

Meanwhile, the Senate’s most senior Republican, Mitch McConnell, said the intelligence committee was already looking into Russian influence on the election, indicating there was no need for a new investigative panel.