President Donald Trump’s lawyers released an overview Thursday of what they say is an “unprecedented” attempt to cooperate with the special counsel and congressional Russia probes.

Twenty White House staffers, including eight from the White House counsel’s office, have sat for voluntary interviews with investigators, the overview said. Those interviews at Robert Mueller’s office include White House counsel Don McGahn, communications director Hope Hicks, senior policy adviser Stephen Miller and former chief of staff Reince Priebus, according to previous CNN reports.

Another 17 campaign employees and 11 other individuals affiliated with the Trump campaign gave interviews to Mueller’s office or during congressional investigations.

The public accounting comes as Trump’s attorneys negotiate the terms of the President’s appearance before the special counsel.

Three former campaign advisers have been hit with charges in the Mueller probe, as well as one senior White House staff member. As Mueller’s team has investigated potential Russian collusion with Trump’s campaign, it has scheduled individuals for voluntary interviews with the FBI and prosecutors, and compelled some people to testify before a federal grand jury.

The White House’s overview Thursday did not describe its interactions with the grand jury, which can approve indictments and subpoenas during an investigation and is still seated in Washington, DC. The congressional probes included in the lawyers’ overview are those by the Senate Intelligence Committee, the House Intelligence Committee and the Senate Judiciary Committee.

So far, the White House has turned more than 20,000 pages of material to Mueller’s office. That includes 1,601 documents about Russia and Michael Flynn, the former national security adviser who pleaded guilty to lying to investigators, and 1,245 documents about James Comey, the former FBI director who was fired by the President.

The Trump campaign gave 1.4 million pages of documents to Mueller and congressional committees received 28,000 documents from the campaign and presidential transition.

The last document collection lawmakers on Capitol Hill received came in late September, and some documents were withheld because they were privileged material, the White House lawyers’ overview said.

In all, Mueller’s office has collected millions of documents, from the White House and through other subpoenas and seizure warrants, in its wide-ranging probe of possible Russian collusion.

Among the charges already in the court system, Flynn and former campaign staffer George Papadopoulos pleaded guilty, while Trump campaign chairman and deputy campaign chair Paul Manafort and Rick Gates have pleaded not guilty.

Mueller’s office has released two status reports in the Manafort and Gates case — which is unrelated to the campaign — that reflect its own counts of documents and other data collected. In its last update for that case, Mueller’s team said it had turned over to the defense more than a half-million documents.