WASHINGTON (AP) — The House Judiciary Committee is expected to file a lawsuit Friday seeking secret grand jury material underlying former special counsel Robert Mueller's report.

Committee Chairman Jerrold Nadler says his panel also will go to court next week to try to enforce a subpoena against former White House counsel Donald McGahn, a key Mueller witness.

Nadler says Mueller's House testimony this week showed there was "considerable collusion" between Donald Trump's 2016 presidential campaign and Russians and that Trump "engaged in multiple acts of obstruction of justice."

Nadler tells CNN his committee is pursuing the grand jury material to "lay the evidence in detail before the American people."

Trump has denied there was any obstruction or collusion and has criticized Mueller's probe. The White House has claimed "absolute immunity" for McGahn.