It was unclear whether his tweet about being under investigation was based on direct knowledge or new media reports that suggest Mueller is examining whether the president obstructed justice by firing Comey.
Rod Rosenstein, the deputy attorney general, appointed former FBI Director Robert Mueller as a special prosecutor in an investigation of alleged collusion between Trump associates and Russian Federation in the 2016 election.
"Americans should exercise caution before accepting as true any stories attributed to anonymous 'officials, ' particularly when they do not identify the country-let alone the branch or agency of government-with which the alleged sources supposedly are affiliated", the statement said.
The Justice Department's investigation into Russian involvement in the 2016 election is looking at Kushner's multiple roles in the Trump administration, including the Trump campaign's 2016 data analytics operation; his relationship with former national security adviser Michael Flynn; and Kushner's own contacts with Russians, according to United States officials briefed on the probe.
It wasn't clear whether the president was basing his tweet on direct knowledge that he is under investigation, or on reports this week that special counsel Robert Mueller is examining whether the president obstructed justice by firing Comey last month amid the ongoing Russian Federation investigation.
Rosenstein was also the author of a letter in May to Trump criticizing the performance of FBI Director James Comey.
The latest White House crisis struck on the evening of Trump's 71st birthday, after a day in which he had won plaudits for his handling of the shooting of Republican Congressman Steve Scalise.
A weekend at the rustic mountain getaway is a far cry from the president's normal routine of jetting off to one of his lavish resorts, mainly Mar-a-Lago in Florida. Last month, news surfaced that Kushner may have discussed creating a secret communications channel between the Trump transition team and the Kremlin with Kislyak.
Kushner's attorney, Jamie Gorelick, told the Washington Post "we don't know what this report refers to". "Sad!" the president tweeted Friday.
The Democratic National Committee, in a statement Friday, said that Rosenstein, who has authority over Mueller, needs to recuse himself from the Russian Federation investigation and that control of the investigation should not be given to another presidential appointee.
A source on Trump's legal team attempted to clarify the missive, claiming he was reacting to media reports about the investigation rather than offering public confirmation.
Firing Mueller would just compound the Trump administration's growing problems.
Trump fired Comey on May 9, but later in an interview on NBC said that the Russian Federation probe was on his mind when he made the decision to fire Comey. Those associates include former national security adviser Michael Flynn, campaign chairman Paul Manafort, foreign policy aide Carter Page and outside adviser Roger Stone.
Trump's tweet comes less than a day after a odd statement from a senior official in his administration.
Blunt was asked if he believes the Russian investigation is a "witch hunt", as Trump has repeatedly tweeted.
On Thursday, Russian President Vladimir Putin said Comey had presented no evidence to prove that Moscow meddled in the U.S. election, adding that Washington had tried to influence Russian elections "year after year".
Regardless of the chaos that could ensue in the leadership of the Justice Department, Mueller's investigation appears insulated, and much of the work of the department done by US attorneys across the country will continue, Cramer said.