AKIPRESS.COM - A US Senate panel investigating Russian interference in last year's election has issued a formal demand for documents from President Donald Trump's former national security adviser, BBC reported.

Michael Flynn has failed to voluntarily co-operate with the investigation, the Senate Intelligence Committee says.

He was forced to resign in February after failing to disclose the content of his talks with Russian diplomats.

Meanwhile, the fallout continues over the firing of the FBI director.

The White House maintained that James Comey was removed on Tuesday for his handling of the inquiry over Hillary Clinton's emails.

But US media reported that he had recently asked the Justice Department for more resources for his Trump-Russia investigation.

The Senate Intelligence Committee said it issued a subpoena after Mr Flynn rejected its request on 28 April to submit documents relevant to the investigation.

Mr Flynn, a retired army lieutenant-general, misled the White House about discussing US sanctions against Russia with the country's envoy, Sergei Kislyak, before Donald Trump's inauguration in January.