Trump: US Congress Should Summon Obama Over Flynn Case

US President Donald Trump said Thursday that former President Barack Obama should testify before Congress because of recent intelligence revelations.

"If I were a Senator or Congressman, the first person I would call to testify about the biggest political crime and scandal in the history of the USA, by FAR, is former President Obama. He knew EVERYTHING," Trump said on Twitter.

While Trump was unclear about the alleged "crime" to which he was referring, he called on the Republican head of the Senate Judiciary Committee to begin the process.

"Do it @LindseyGrahamSC, just do it. No more Mr. Nice Guy. No more talk!" Trump urged.

The president's call was swiftly rejected by Graham who said he does not "think now's the time for me to do that."

"I don't know if that's even possible. I have grave concerns about the role of executive privilege and all kinds of issues," Graham told the Politico website. "I understand President Trump's frustration, but be careful what you wish for. Just be careful what you wish for."

Acting US Director of National Intelligence Richard Grenell on Wednesday released a list of former Obama administration officials accused of "unmasking" former National Security Advisor Michael Flynn.

The release comes as Trump continues to rail against what he calls "Obamagate," though he has repeatedly struggled to clearly state what the scandal entails. But he has repeatedly sought to frame the Russia investigation that ensnared Flynn as a "deep state" plot against him.

The Justice Department made the exceptionally rare move last week to dismiss the case against Flynn, after he pleaded guilty to lying to federal investigators.

Flynn has since sought to withdraw his 2017 guilty plea.

The federal judge overseeing his case on Wednesday appointed a retired judge to take up the case against the department's motion.

*Michael Hernandez contributed to this report from Washington -