US election officials have said the 2020 White House vote was the "most secure in American history", rejecting President Donald Trump's fraud claims.
"There is no evidence that any voting system deleted or lost votes, changed votes, or was in any way compromised," a committee announced.
They spoke out after Mr Trump claimed without proof that 2.7 million votes for him had been "deleted".
He has yet to concede to the president-elect, Democrat Joe Biden.
The result of the 3 November election was projected by all the major US TV networks last weekend.
On Friday, the BBC projected Mr Biden to have won Georgia and Mr Trump to have won North Carolina.
Mr Biden was earlier projected to have won Arizona. His total is now 306 electoral college votes, with Mr Trump at 232.
It is the first time Arizona and Georgia have voted Democrat since 1996 and 1992 respectively.
Mr Trump has launched a flurry of legal challenges in key states and levelled unsubstantiated allegations of widespread electoral fraud.
In another development, a group of more than 150 former national security officials has warned that delaying the transition posed "a serious risk to national security".
In a letter, they urged the General Services Administration - the government agency tasked with beginning the transition process - to officially recognise Joe Biden and his running mate Kamala Harris so that they could access "pressing national security issues".
Meanwhile, China has finally extended its congratulations to Mr Biden and Ms Harris after days of silence. "We respect the choice of the American people," a foreign ministry spokesman said. Russia has said it wants to wait for an "official result".
Why is the statement important?
The announcement from US election officials marks the most direct rebuttal from federal and state officials of President Trump's unsubstantiated claims of election fraud.
Thursday's joint statement was released by the Election Infrastructure Government Co-ordinating Council - which is made up of senior officials from the Department of Homeland Security and the US Election Assistance Commission as well as state-level officials who oversee elections and representatives of the voting machine industry.
"The November 3rd election was the most secure in American history. Right now, across the country, election officials are reviewing and double checking the entire election process prior to finalizing the result," the group said.
"While we know there are many unfounded claims and opportunities for misinformation about the process of our elections, we can assure you we have the utmost confidence in the security and integrity of our elections, and you should too," it added, without naming Mr Trump directly.
"When you have questions, turn to elections officials as trusted voices as they administer elections."
The statement was posted to the website of the Cybersecurity and Infrastructure Security Agency (Cisa), which is part of the Department of Homeland Security.
The head of Cisa, Christopher Krebs, has reportedly incurred the White House's displeasure over a Cisa website called Rumor Control, which debunks election misinformation.
On Thursday, Mr Krebs shared a post by an election law expert that said: "Please don't retweet wild and baseless claims about voting machines, even if they're made by the president."
Cisa assistant director Bryan Ware stepped down on Thursday. The White House had asked for his resignation earlier this week, Reuters reports. Mr Krebs expects to be fired, the news agency adds.
Hours before the statement was released, Mr Trump tweeted that voting software used in 28 states had deleted millions of votes for him, but presented no evidence for the stunning claim, which appeared to originate from the obscure TV network One America News and was flagged by Twitter.
The claim was linked to the miscounting of votes in one Republican-leaning Michigan county. Unofficial results initially favoured Mr Biden but were later corrected in President Trump's favour. State election officials acknowledged what had happened, saying human error was to blame, rather than a software malfunction.
For Trump's advisers it's business as usual
At the White House, President Trump's advisers discuss his trade policies and act as if he will remain their boss for the next several years and they will still have jobs on the premises.
One of the president's economic advisers, Peter Navarro, said on Fox Business this morning that they are operating under the assumption that "there will be a second Trump term".
When I saw Navarro recently in front of the West Wing, he seemed equally confident about his future in the building. He refused to answer questions, and he insulted journalists, just as he had always done.
Then he waved vigorously at me as he slipped into the West Wing, a place where he was among friends.
People outside of the White House and in other parts of town say their time is almost over. But for those who are inside the West Wing, it's business as usual.
Are Republicans backing Trump?
A small but growing number of Republicans are backing calls for the president-elect to be given daily intelligence briefings.
Senator Lindsey Graham, a key Trump ally, was among those saying Mr Biden should start receiving the secret presidential memo, as is usual with incoming presidents.
Republican Senators Chuck Grassley, John Cornyn and John Thune agreed, although House Minority Leader Kevin McCarthy said Mr Biden was "not president right now" and should wait.
Between 10 and 20 Republicans in Congress have now either congratulated Mr Biden or accepted there must be moves towards a transition. But most have yet to acknowledge the president-elect's win.
A chorus of senior Democrats have condemned this:
- Former President Barack Obama said senior Republicans were undermining democracy by going along with President Trump's claims of fraud
- House Speaker Nancy Pelosi meanwhile said the "absurd circus" meant the coronavirus pandemic was being neglected.
- Senator Chris Coons told CNN some Republicans had been asking him to congratulate Mr Biden on their behalf because they did not feel able to do so publicly.
- Senate minority leader Chuck Schumer said Republican politicians were "deliberately casting doubt on our elections for no other reason but fear of Donald Trump".
Capitol Hill reporters say Republican lawmakers are anxious not to alienate the Trump base, given that the president just won more votes than any incumbent ever, even though he is projected to lose.
Party bigwigs are also said to be hoping that Mr Trump will help campaign for two Senate run-off elections in January in Georgia that will decide whether Republicans retain control of the upper chamber.
Mr Biden is 5.3 million votes ahead of Mr Trump - about 3.4%, and is well beyond the hurdle of 270 electoral college votes required to win the presidency.
President Trump has kept a low key public profile since the election. Reports suggest he has told friends he wants to start a digital media company to take on the conservative network Fox News, whose full support he now feels to be lacking.
According to CBS News, Mr Trump is also openly discussing a possible 2024 campaign to retake the presidency.
What has Biden been up to?
On Thursday he spoke with Pope Francis, who offered his "blessings and congratulations". Mr Biden will be only the second Roman Catholic president of the US.
He also spoke with congressional Democratic leadership about the need for a coronavirus stimulus package as the daily US caseload from the disease soared to a new record of more than 150,000.
He spent the day huddled with his transition team in Wilmington, Delaware, where he had been planning cabinet appointments.
On Wednesday he picked veteran Democratic operative Ron Klain to be his White House chief of staff.