US President Donald Trump has said he was not told of intelligence that a Russian military spy unit offered bounties to Taliban-linked militants to attack coalition forces in Afghanistan - including US troops - because intelligence officials did not find the information credible.
"Intel just reported to me that they did not find this info credible, and therefore did not report it to me or @VP," Mr Trump said in a tweet on Sunday night, referring to Vice President Mike Pence.
He added that he considers such reports "possibly another fabricated Russia Hoax" spread by the "Fake News ... wanting to make Republicans look bad!!!"
Mr Trump had earlier tweeted he had not been briefed about the intelligence, but he did little to clarify whether the administration was denying the assessment existed or simply that he knew anything about it.
'The Washington Post' reported the Russian bounties offered to Taliban-linked militants to kill coalition forces in Afghanistan are believed to have resulted in the deaths of several US service members, according to intelligence gleaned from American military interrogations of captured militants in recent months.
Several people familiar with the matter said it was unclear exactly how many US or coalition troops from other countries may have been killed or targeted.
The intelligence was passed up from the US Special Operations forces based in Afghanistan and led to a restricted high-level White House meeting in late March, the people said.
Asked to comment, John Ullyot, a National Security Council spokesman, said "the veracity of the underlying allegations continue to be evaluated". The CIA and the Defence and State departments declined to comment.
Russia and the Taliban have denied the existence of the programme.
Mr Trump's late-night tweet came in response to one by Republican Senator Lindsey O Graham, one of many legislators from both parties who called on the Trump administration to provide an explanation of what had transpired.
"Imperative Congress get to the bottom of recent media reports that Russian GRU units in Afghanistan have offered to pay the Taliban to kill American soldiers with the goal of pushing America out of the region," Mr Graham tweeted.
Yesterday, House Speaker Nancy Pelosi said she had written to senior intelligence officials requesting a briefing for all House members about what she characterised as a "significant threat to American troops and our allies".
"The questions that arise are: was the president briefed, and if not, why not, and why was Congress not briefed," Ms Pelosi said in her letter, a copy of which was released by her office. "Congress and the country need answers now."
She added she wants to know "what options are available to hold Russia accountable."
White House press secretary Kayleigh McEnany said during an appearance on Fox News that Congress would be briefed on the situation later in the day, adding: "I think that will clear up a lot of the false reporting."
She did not specify which members of Congress would be briefed.
Ms McEnany said media reports have been based on "alleged intelligence that was never briefed to the president of the United States", and she criticised the media for "spewing out" false information.
She said that as a matter of practice, Mr Trump is briefed only on intelligence that is found to be "verifiable and credible."
Separately yesterday, House armed services committee chairman Adam Smith sought "detailed answers" from the Defence Department.
"The American people - and our service members - deserve to know the truth about what the White House knew about these Russian operations that may have directly resulted in the deaths of American service members," Mr Smith said.
"We must find out exactly what was known, and when it was known to hold the appropriate administration officials and the Russian government accountable."