Deputy Attorney General Rod Rosenstein has called in the Department of Justice’s inspector general in response to a tweet by President Trump demanding an investigation.

Rosenstein made the request Sunday for a probe into whether there was any improper surveillance of the Trump campaign in 2016, according to The Hill.

Trump had tweeted earlier Sunday that he would be “officially” requesting an investigation into whether “the FBI/DOJ infiltrated or surveilled the Trump Campaign for Political Purposes.”

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! — Donald J. Trump (@realDonaldTrump) May 20, 2018

In a statement a few hours later, Rosenstein said: “If anyone did infiltrate or surveil participants in a presidential campaign for inappropriate purposes, we need to know about it and take appropriate action.” The attorney general, Jeff Sessions, has recused himself from Russia-related matters.

DOJ spokeswoman Sarah Isgur Flores added 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.”

The probe will “include determining whether there was any impropriety or political motivation in how the FBI conducted its counterintelligence investigation of persons suspected of involvement with the Russian agents who interfered in the 2016 presidential election,” Flores noted.

The inspector general will be expanding the original probe into alleged FBI surveillance abuse which was launched in March and focused on whether the department abused the Foreign Intelligence Surveillance Act, using the so-called Steele dossier to obtain a warrant to surveil former Trump campaign associate Carter Page.

The president spent the last few days hammering the topic on Twitter, as he continues to maintain special counsel Robert Mueller’s probe is nothing more than a “witch hunt.”