Deputy Attorney General Rod Rosenstein confirmed over the weekend he was directing the Justice Department's internal watchdog to begin investigating whether a government asset was placed in the Trump campaign for political motivations.
Mr. Trump added in his tweet on Sunday that he will ask DOJ to investigate whether any potential surveillance was ordered "by people within the Obama administration!" That probe began after Republican lawmakers alleged that former Trump campaign adviser Carter Page was improperly targeted for surveillance in the early days of the Russian Federation investigation. The Washington Post reported Friday that the source, a retired American professor, had contacts with three Trump advisers during the 2016 campaign.
Republican lawmakers have alleged the FBI's wiretap requests were based chiefly on information from a controversial dossier prepared by former British spy Christopher Steele, who had been paid for the work by the campaign of Hillary Clinton and the Democratic National Committee.
"If anyone did infiltrate or surveil participants in a presidential campaign for inappropriate purposes, we need to know about it and take appropriate action", Rosenstein said.
DOJ spokeswoman Sarah Isgur Flores said in a separate statement that "the Inspector General will consult with the appropriate U.S. Attorney if there is any evidence of potential criminal conduct". Although Trump has suggested the source was embedded in his campaign, United States officials have told CNN that was not the case.
There was also concern among Trump-aligned lawmakers that White House Chief of Staff John Kelly and White House counsel Donald McGahn may be trying to "water down" the president's position as a way of avoiding a potential crisis over highly sensitive materials that the Justice Department has always been wary of releasing, according to one person close to those Republicans.
Devin Nunes and Trey Gowdy did not take up an invitation to meet with the Justice Department last week, citing leaks within the agency. But intelligence officials say turning over the documents would put the source at risk, according to The Washington Post. However, his lawyer, Rudy Giuliani, said neither he nor the president knows for sure if it really happened.
As a pair of Post articles, dated May 8 and 9, explained, the DOJ has refused to provide the documents, concerned that the safety of the US citizen source could be endangered, and that ongoing intelligence investigations could be compromised. It's now folding Trump's demand into that investigation.
Several Republicans have called for an end to Mueller's investigation, which the president has repeatedly deemed a "witch hunt". Negotiations between the House Republicans and the Justice department appeared to stall last week ahead of Trump's tweet - an apparent reversal of the White House's initial policy.
It is unclear at this time what the outcome of the inspector general's investigation will be.
That review will assess whether the Federal Bureau of Investigation and the Justice Department complied with the law and their own policies in requesting and carrying out the surveillance.
The White House said Monday that top FBI and Justice Department officials have agreed to meet with congressional leaders and "review" highly classified information the lawmakers have been seeking as they scrutinize the handling of the Russian Federation investigation.