Joe Biden has described the midterm results so far as a “good day for democracy” and a “good day for America”.
Speaking at the White House on Tuesday afternoon, the president said the results, although still unclear, represent a “clear and unmistakable message to preserve our democracy”.
“The American people have spoken and shown that democracy is who we are,” he said.
But he added that “the voters were also clear that they’re still frustrated, I get it, it’s been a really tough few years for this country”.
In reference to Donald Trump’s claims he “stole” the last elections, he said vote counters and officials “did their job and fulfilled their duty… without any interference”.
He also said he would make a decision on whether he would run for a second term early next year.
The Republicans are set to take control of the House of Representatives, with 221 seats to the Democrats’ 214, according to NBC News.
Although this would thwart the president’s legislative programme, it is a much smaller loss than some had predicted.
The race for the Senate is still in the balance, however, with four seats left to declare and the Republicans leading by two in those announced so far.
Georgia is unlikely to be decided until 6 December, as strict state laws require a run-off if no candidate reaches 50%.
‘Democrats had strong night’
Mr Biden said the Democrats “had a strong night” despite losing seats.
“We don’t know all the results yet, but here’s what we do know, the press were predicting a giant red wave and it didn’t happen,” he said.
“You were somewhat miffed by my obsessive optimism, but I thought we were going to do fine.”
He said that the “future of America is too promising” for it to be “trapped in endless political warfare”.
While he would not compromise on healthcare or abortion, he said: “I’m going to do everything within my power to unite the country.
“I’m going to continue to work across the aisle to support the American people. Regardless of what the final tally of these elections show, I am prepared to work with my Republican colleagues.
“And the American people have made clear they expect Republicans to work with me as well.”
He addressed the nation after Donald Trump described his candidates’ results so far as “somewhat disappointing”.
Almost all the people Mr Trump chose to endorse appear to have fared worse than the Republicans he did not back.
Reports claim behind the scenes he is “livid” and “angry” at his wife Melania.
Speaking from his Mar-a-Lago home, the former president claimed the results were a “very big victory” for him personally.