Republicans will maintain their six-year control over the US House of Representatives, according to early network projections on Tuesday night, as the party also put up an unexpectedly tough fight to protect its majority in the US Senate.
The ABC and NBC television networks said Republicans, as widely projected in opinion polls, would keep control of the House, which has been in their hands since 2011.
Winners had been declared so far in 16 Senate races, with Democrats making a net gain of only a single seat so far, but some other opportunities for them remained undecided. Several key races were seen as too close to call.
Party dominance in Congress will be a crucial determinant of the policy-making outlook for the next president, whether it is Democrat Hillary Clinton or Republican Donald Trump.
Democrats picked up their first Senate seat from Republicans as Representative Tammy Duckworth, as expected, defeated Senator Mark Kirk in Illinois, according to the major TV networks.
Duckworth is a double-amputee Iraq war veteran. With her victory, Democrats need to pick up four more seats from Republicans in order to win a majority in the Senate.
The networks projected that in Indiana, former Senator Evan Bayh failed in his bid to return to the Senate, losing to Republican Representative Todd Young. The two candidates had been vying to replace Republican Dan Coats, who retired. Bayh's loss was a missed opportunity for Democrats to gain a seat.
In Florida, incumbent Senator Marco Rubio, who ran unsuccessfully for the Republican presidential nomination earlier this year, was declared the winner and re-elected.
PORTMAN RE-ELECTED IN OHIO
Major TV networks said Republican Senator Rob Portman, who refused to campaign with Trump, was re-elected in Ohio.
Also projected as winners by the networks, as expected, were Republican Senators Rand Paul in Kentucky, Tim Scott in South Carolina, James Lankford in Oklahoma, Richard Shelby in Alabama, John McCain in Arizona, John Hoeven in North Dakota, Jerry Moran in Kansas and John Thune in South Dakota.
Democrats Patrick Leahy in Vermont, Chris Van Hollen in Maryland, Richard Blumenthal in Connecticut and Chuck Schumer in New York were declared winners.
Continued Republican dominance in Congress could stymie any legislative agenda pursued by Clinton, if she is elected. A Trump victory, with a Republican Congress, could spell a swift demise for Democratic President Barack Obama's health reforms.
Republicans have controlled the 100-seat Senate since 2015, but they had to defend far more seats this year than did the Democrats. Some analysts had raised the possibility of the 2016 election season ending with a 50-50 split in the Senate.
In such an outcome, the new US vice president - either Democrat Tim Kaine or Republican Mike Pence - would be the tiebreaker in the Senate and determine control of that chamber.
To win Senate control, Democrats would have to score a net, five-seat gain. Republicans hold 54 Senate seats to 44 Democratic seats and two independents who align with Democrats.