Two US Republican Senators are facing calls to resign over allegations they used insider knowledge to sell shares before prices fell due to coronavirus fears.
Richard Burr reportedly dumped up to $1.7m (£1.45m) of stocks last month.
Kelly Loeffler is reported to have sold holdings worth up to $3m in a series of transactions beginning the same day as a Senate briefing on the virus.
Both Senators have denied any impropriety.
Under US law, it is illegal for members of Congress to trade based on non-public information gathered during their official duties.
Mr Burr, chairman of the Senate Intelligence Committee, has also come under fire after US outlet NPR obtained a recording of him warning a group of wealthy constituents last month about the dire economic impact of the coronavirus, at a time when the Trump administration was publicly downplaying the threat. He also told the group to curtail their travel.
In response, Mr Burr has accused NPR of “misrepresenting” his speech.
The latest revelations come after an investigation by ProPublica into his financial filings.
As chairman of the Senate Intelligence Committee, Mr Burr receives nearly daily briefings on threats to US national security.
On 7 February, shortly after the first case of coronavirus was reported, Mr Burr wrote on Fox News that the US government was “better prepared than ever” to tackle an outbreak.
But a week later, when President Donald Trump assured the public that the virus would not hit America hard, Mr Burr and his wife sold at least $628,000 and as much as $1.72 million in stocks. Two weeks after that, he gave the speech obtained by NPR.
Among those calling for his resignation and investigation are Fox News host Tucker Carlson, who has historically been a vocal supporter of the Trump administration.
Several of the stocks that Mr Burr sold, including in the hotel and travel industry, have since lost value.
On Friday, Mr Burr again responded, tweeting that his decision to sell stock was made “solely based on public news reports”. He specifically cited the Asia coverage provided by the CNBC network.
“Understanding the assumption many could make in hindsight however,” he said in a short statement, “I spoke with the chairman of the Senate Ethics Committee this morning and asked him to open a complete view of the matter with full transparency”.
