"I hereby demand, and will do so officially tomorrow, that the Department of Justice look into whether or not the FBI/DOJ infiltrated or surveilled the Trump Campaign for Political Purposes - and if any such demands or requests were made by people within the Obama Administration!"
On whether there was an "informant" in the 2016 presidential campaign, Giuliani told CNN, "I don't know for sure, nor does the president, if there really was one", though he said they have always been told there was "some kind of infiltration".
"It would be at best irresponsible, and at worst potentially illegal, for members of Congress to use their positions to learn the identity of an FBI source for the goal of undermining the ongoing investigation into Russian interference in our election", Warner wrote in a statement. Used Informant to Investigate.
The revelation of the timeframe comes with Mr Mueller seeking to interview Mr Trump about claims he obstructed justice.
Papadopoulos was charged previous year in special counsel Robert Mueller's investigation and pleaded guilty to lying to the FBI.
It was not immediately clear if that move would satisfy Trump, or if any further demands could lead to a confrontation with FBI Director Christopher Wray or Deputy Attorney General Rod Rosenstein, who is overseeing the Mueller investigation.
Jeff Sessions, the U.S. attorney general, and Mr Rosenstein, his deputy, have both been figures of Mr Trump's public anger in the past.
Deputy Attorney General Rod Rosenstein made the request for the DOJ IG to intervene.
Trump's latest demand came amid a series of tweets yesterday denouncing a "witch hunt" that, he said, had found no collusion by his campaign with Russian Federation.
Since at least early April, Nunes has been demanding from the Justice Department un-redacted versions of the materials detailing the launch of the Russian Federation probe.
Nunes said he and Gowdy canceled the meeting after they were informed that DoJ had decided not to provide the documents. Giuliani defended the president's actions. "To me, there's not much of a difference between an informant's ongoing collection of information in a surreptitious way or a spy". The article cites work by Republican Rep. Devin Nunes of California, an ardent Trump supporter and chairman of the House Intelligence Committee, who has demanded information on an FBI source in the Russian Federation investigation.
Committee Democrats said Republicans did not conduct the 14-month probe in good faith.
In a statement yesterday, Rosenstein said he intends to refer any request to the inspector general, which is already looking into claims of political motivations in the investigation of former Secretary of State Hillary Clinton's use of a private email server.
Trump fully endorses that view and first addressed it in a string of tweets in March 2017, in which he alleged the Obama administration had ordered a wiretap on Trump Tower, his business and campaign headquarters.