Mueller is investigating alleged Russian interference in the 2016 US presidential election and possible collusion with the Trump campaign.
Former FBI director James Comey told Congress last week he believed he was fired by Trump to undermine the agency’s Russia probe.
The Post, citing five unnamed officials, reports that Dan Coats, the director of national intelligence, Mike Rogers, the head of the National Security Agency, and Richard Ledgett, the former deputy director at the NSA, had agreed to be interviewed by Mueller’s investigators as early as this week.
The obstruction of justice investigation into Trump began days after Comey was sacked on May 9, the Post said.
Trump’s legal team quickly denounced the story.
“The FBI leak of information regarding the President is outrageous, inexcusable and illegal,” spokesman Mark Corallo said.
A spokesman for Mueller declined to comment.
Several legal experts told Reuters that Comey’s testimony that Trump expected loyalty and told Comey he hoped he could drop an investigation of a former top aide could bolster obstruction of justice allegations against Trump.
After Comey’s testimony, Trump said he had been vindicated because his former FBI director confirmed telling Trump on three occasions that he was not under investigation.
An obstruction of justice finding could form the basis for Trump’s impeachment but such a step would face a steep hurdle because it would require approval by the US House of Representatives, which is controlled by Trump’s fellow Republicans.
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