The Justice Department notified former Trump administration officials this week that they could testify to the various committees investigating the Jan. 6 attack on the Capitol, according to a letter obtained by The New York Times.

Witnesses can give “unrestricted testimony” to the House Oversight and Reform Committee and the Senate Judiciary Committee, the department said in a letter this week. Both panels are scrutinizing the Trump administration’s efforts to overturn the election in its final days and the events leading up to the Jan. 6 attack on the Capitol.

The decision runs counter to the views of former President Donald J. Trump, who has argued that his decisions and deliberations are protected by executive privilege. It also sets up a potential court battle if Mr. Trump sues in a bid to block any testimony.