Election security officials have no evidence that ballots were deleted or lost by voting systems in this month's U.S. election, two security groups said in a statement released on Thursday by the lead U.S. cybersecurity agency.

"There is no evidence that any voting system deleted or lost votes, changed votes, or was in any way compromised," the groups said about the Nov. 3 election won by Joe Biden, a Democrat.

Republican President Donald Trump has repeatedly made unsubstantiated claims of electoral fraud and has yet to concede.

The groups, the Election Infrastructure Government Coordinating Council Executive Committee (GCC) and the Election Infrastructure Sector Coordinating Council (SCC), said the election was the most secure in U.S. history.

"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," the groups said in the statement released by the Department of Homeland Security's Cybersecurity and Infrastructure Security Agency (CISA).

CISA has drawn the ire of the Trump White House over a website it runs dubbed "Rumor Control" which debunks misinformation about the election, according to the three people familiar with the matter.

Top U.S. cybersecurity official Christopher Krebs, who worked on protecting the election from hackers, has told associates he expects to be fired, sources familiar with the matter told Reuters.

White House officials have asked for content to be edited or removed that pushed back against numerous false claims about the election, including that Democrats are behind a mass election fraud scheme. CISA officials have chosen not to delete accurate information.

The security groups said all the states with close results in the race have paper records of each vote, which can be counted if necessary.