© Reuters
White House National Security Advisor Michael Flynn
House Oversight Chairman Jason Chaffetz has requested that the Department of Justice launch a formal investigation into the possible leak of classified information following the resignation of former National Security Adviser Michael Flynn.

In a letter to the DOJ's Inspector General Michael Horowitz on Wednesday, Chaffetz and House Judiciary Committee Chair Bob Goodlatte requested an "immediate investigation" into the "potentially classified national security information" that hit the press before Flynn's resignation.

"We have serious concerns about the potential inadequate protection of classified information here," the Republicans wrote. "In light of this, we request that your office begin an immediate investigation into whether classified information was mishandled here."

US President Donald Trump took to Twitter Wednesday to criticize the reporting of classified information that he claims is being leaked by "un-American" "intelligence" agencies.

The letter cites media reports about Flynn's calls with Russian Ambassador Sergey Kislyak and the DOJ's warrant application from the Foreign Intelligence Surveillance Court to intercept electronic records from Russian banks as examples of information that "may come from classified intelligence products".

Democrats have called for an investigation into Flynn's conversations with Russian officials, however Chaffetz has said he has no plans for the oversight committee to look into them.