Top Congressional Democrats are calling on Justice Department and FBI officials to give them assurances that they did not give President Trump or his legal team information regarding the Mueller investigation or the classified briefing they received regarding the FBI's use of an informant during Trump's presidential campaign.

The letter pointed to the Trump legal team's call to review classified documents regarding Stefan Halper, the informant who had contact with Trump advisers, and asked the DOJ and FBI for written assurances that they did not tell Trump, his legal team or White House lawyers about the information.

The letter to Deputy Attorney General Rod Rosenstein and FBI Director Christopher Wray was signed by by Senate Minority Leader Chuck Schumer, D-N.Y., House Minority Leader Nancy Pelosi, D-Calif., Sen. Mark Warner, D-Va., ranking member on the Senate Intelligence Committee, and Rep. Adam Schiff, D-Calif., ranking member on the House Intelligence Committee.

“We remain deeply troubled by President Donald Trump and his legal team’s persistent efforts to interfere with the Special Counsel’s ongoing investigation and undermine your agencies’ lawful activities,” the four lawmakers wrote in the letter.

“These developments leave us concerned that, through his legal team or otherwise, the President will continue to pressure your agencies to divulge investigative information which he, his attorneys, and his congressional allies then could manipulate or even disclose publicly for the President’s benefit," they wrote. "That would be a terrible abuse of power.”

The letter comes after Rudy Giuliani, the president's personal lawyer, said recently that the White House wants a briefing on the materials and that Trump's interview with special counsel Robert Mueller would only happen if they see the classified information.

The "Gang of Eight" — the top eight congressional leaders in both chambers — was briefed on the materials and the informant on May 24. The Democratic leaders asked that their request be met by Monday at 5 p.m.