US President Donald Trump has played down the importance of an ex-campaign aide indicted in the Russia inquiry.
He said his onetime foreign policy adviser George Papadopoulos was a "low level volunteer" and "liar". Mr Trump once called him an "excellent guy".
Papadopoulos, 30, this month pleaded guilty to lying to the FBI about his Kremlin-related contacts.
Two other ex-aides have been charged as part of the investigation into alleged Russian meddling in the US election.
The other two, former campaign chief Paul Manafort and Rick Gates, appeared in court on Monday to deny charges including conspiracy and money laundering.
In Tuesday morning's tweets, Mr Trump attempted to deflect scrutiny on to the Democratic Party, or his tax reform proposals.
He tweeted: "The Fake News is working overtime. As Paul Manaforts [sic] lawyer said, there was 'no collusion' and events mentioned took place long before he came to the campaign.
"Few people knew the young, low level volunteer named George, who has already proven to be a liar. Check the DEMS!"
Papadopoulos appears in a photo that Mr Trump shared on social media of himself in March 2016 hosting a national security meeting with his foreign policy team:
In court documents released on Monday, federal investigators said Russian nationals had contacted Mr Papadopoulos to gain influence with the Trump campaign.
They offered "dirt" in the form of "thousands of emails" on Democratic presidential candidate Hillary Clinton in April 2016, according to an indictment.
That was two months before a trove of embarrassing emails related to Mrs Clinton's campaign were leaked after alleged Russian hacking of Democratic accounts.
Papadopoulos, who secretly pleaded guilty weeks ago to lying to the FBI about those contacts, has been co-operating with investigators for months.
Despite White House hopes to the contrary, there is no sign that Justice Department special counsel Robert Mueller's inquiry is near to completion.
Aaron Zelinsky, a prosecutor on Mr Mueller's team, told Papadopoulos' plea hearing this month: "There's a large-scale, ongoing investigation of which this case is a small part."
In Moscow, Russian foreign ministry spokeswoman Maria Zakharova poured scorn on the US in the wake of the indictments.
She referred to "photographs" of Osama Bin Laden meeting White House officials, an apparent reference to a faked photo of Hillary Clinton shaking hands with the late al-Qaeda chief.
Ms Zakharova also pointed out that the Manafort indictment contained an error.
The charge sheet wrongly stated that Yulia Tymoshenko, the former Ukrainian prime minister, had served as president.