- Video report by ITV News Washington Correspondent Robert Moore
Lawmakers in the US House of Representatives and Senate have convened for the 116th Congress with the most diverse class of politicians in its history.
More women than ever before and a significant number of people from minority backgrounds were swore in on Thursday as Democrats took majority control of the lower chamber.
It came as Nancy Pelosi was returned as House speaker, saying a "new dawn" had been called for in US politics.
In her speech, she did not rule out impeachment proceedings against President Donald Trump.
Democrats are ready to confront President Trump in a new era of divided government, with Republicans still controlling the Senate.
- Watch the 116th Congress being sworn in
This was the first new Congress to convene during a partial government shutdown, now in its 13th day over Mr Trump's demands for money for a southern border wall.
Democrats have promised to end the shutdown by passing a number of budgetary measures - but not money earmarked for the wall.
Ms Pelosi pledged to make Congress work for all Americans.
But her party is also ready to challenge Mr Trump with investigations that threaten the White House agenda.
Ms Pelosi said: "This House will be for the people, to lower health costs and prescription drugs prices, and protect people with pre-existing conditions; to increase paychecks by rebuilding America with green and modern infrastructure — from sea to shining sea."
She also vowed "to restore integrity to government, so that people can have confidence that government works for the public interest, not the special interests".
Vice President Mike Pence swore in newly-elected senators, but Senate Republicans under Majority Leader Mitch McConnell had no plans to consider the House bills to fund the government unless Mr Trump agrees to sign them into law.
That ensures the shutdown will continue, clouding the first days of the new session.
It is a time of stark national political division that some analysts say is on par with the Civil War era.
Battle lines are drawn not just between Democrats and Republicans but within the parties themselves, splintered by their left and right flanks.
Ms Pelosi defied history in returning to the speaker’s office after eight years in the minority, overcoming internal opposition from Democrats demanding a new generation of leaders.
She will be the first to regain the gavel since legendary Sam Rayburn of Texas in 1955.
Mr Trump, whose own bid for 2020 already is underway, faces potential challenges from the ranks of Senate Democrats under Chuck Schumer.
He had little to say as the new Congress was convening, but he did tweet an attack on one of his likely presidential challengers, Senator Elizabeth Warren, mocking her claim to Native American ancestry.