Washington : US lawmakers voted to recommend criminal contempt charges against Donald Trump's former top aide Mark Meadows for refusing to testify before the congressional panel investigating the January 6 assault on the Capitol.

The panel is investigating Trump's efforts to overturn his defeat in the November 2020 election in the run-up to the Capitol riot -- as well as the help he got from Meadows and others. "We've given Mark Meadows every opportunity to cooperate. He's brought this situation on himself," the House January 6 select committee said in a statement ahead of the vote, which went roughly along party lines, with just two Republicans joining every Democrat to hold Meadows in contempt.

The rebuke from the House of Representatives moves the ultra-conservative ex-congressman a step closer to becoming the first White House chief of staff to be prosecuted after leaving the post since H.R. Haldeman in the Watergate scandal nearly 50 years ago.The nine-member select committee, which voted Monday to advance the contempt case, says it is seeking answers about text messages and other communications that Meadows has already acknowledged are not privileged.

Meadows, who served in the House for seven years before decamping to Trump's team in 2020, defied a subpoena requiring him to testify, pointing to an "executive privilege" claim by the Republican former president. That defense, which is theoretically only available to sitting presidents seeking to keep sensitive conversations with aides private, has already been shot down by a federal appeals court.

Investigators say Meadows has given up any right to refuse testimony in any event, as he is promoting a new memoir that includes detailed accounts of January 6 and his conversations with Trump. He has also spoken numerous times about the attack in primetime appearances on Fox News.

In a further sign of the net tightening on figures accused of involvement in the Capitol assault, the Democratic attorney general for the US capital said he was suing the "Proud Boys and Oath Keepers", blaming the far-right groups for the violence. The Meadows case is a federal issue, however, and the 62-year-old Florida native will have to sweat until the Justice Department decides whether prosecutors will take up the House referral.

The department charged former White House strategist Steve Bannon with criminal contempt of Congress less than a month after the House voted to refer him. The Meadows decision may prove less straightforward than the case of Bannon, who was not working for the Trump administration at the time of the riot. Meadows' lawyer George Terwilliger said in a statement his client's refusal to cooperate did not amount to non-cooperation, but rather an effort to "honor" Trump's rejected privilege claims.