President acknowledges he's under investigation

WASHINGTON (AP) - President Donald Trump acknowledged for the first time Friday he is under federal investigation as part of the probe into Russia's election meddling. 

"I am being investigated for firing the FBI Director by the man who told me to fire the FBI Director! Witch Hunt," the president wrote on Twitter.

His morning missive apparently referred to Rod Rosenstein, the deputy attorney general whose role leading the federal investigation has become increasingly complicated. The White House has used a memo he wrote to justify Trump's decision to fire FBI Director James Comey, but that Trump action may now be part of the probe. Thursday night, Rosenstein issued an unusual statement complaining about leaks in the case.

Trump advisers and confidants describe the president as upset over the investigation, insisting he is the target of a conspiracy to discredit his presidency. 

Dianne Feinstein, top Democrat on the Senate Judiciary Committee, said she was "increasingly concerned" Trump will fire both Mueller and Rosenstein.

"The message the president is sending through his tweets is that he believes the rule of law doesn't apply to him and that anyone who thinks otherwise will be fired," Feinstein said. "That's undemocratic on its face and a blatant violation of the president's oath of office."

Aides have counseled the president to stay off Twitter and focus on other aspects of his job. They have tried to highlight the positive reviews he received Wednesday when he made a statesman-like appearance in the White House to address the nation after Rep. Steve Scalise was shot during a congressional baseball practice.

The president has denied he has any nefarious ties to Russia and has also disputed he's attempted to block the investigation into his campaign's possible role in Russia's election-related hacking. 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.

The tweets came shortly after Rosenstein issued his unusual statement that appeared to be warning about the accuracy of such reports.

"Americans should be skeptical about anonymous allegations," Rosenstein said. "The Department of Justice has a long-established policy to neither confirm nor deny such allegations."

The department would not comment on the record on whether Trump, who has complained about leaks on the case, requested the statement. But a department official said no one asked for the statement and Rosenstein acted on his own. The official demanded anonymity because the official was not authorized to be named discussing the deliberations.

Trump has told associates he has the legal authority to fire Mueller. What is clear is he could order the Justice Department to ax Mueller, which may result in Rosenstein's departure and would certainly intensify the investigation. Though some in the White House have preached caution, fearing a repeat of the firestorm over Comey's firing, many in Trump's orbit - including his son Donald Trump Jr. and adviser Newt Gingrich - have deemed Mueller biased and worthy of dismissal.