California election officials are rejecting President-elect Donald Trump’s unfounded claim of “serious voter fraud” in the state.

Without providing any proof, Trump tweeted Sunday that in addition to winning the Electoral College, he also won the popular vote “if you deduct the millions of people who voted illegally.” He later tweeted that there was “serious voter fraud in Virginia, New Hampshire and California.”

PolitiFact California has rated Trump's claim of “serious voter fraud” in California Pants on Fire.

The claim also provoked some strong responses from California election officials.

“It’s this broad-based allegation with nothing to back it up,” says Los Angeles County registrar Dean Logan. “When individuals register to vote in California, they do provide either their California driver’s license number or the last four digits of their social security number. That is verified against governmental databases, as well as their signature on a legal oath attesting to their eligibility.”

“Procedures are in place to investigate any real voter fraud,” Secretary of State Alex Padilla told NPR’s All Things Considered Monday. “But as the evidence has shown, the cases of voter fraud across the country are statistically minimal.”

Logan says California law lays out how to challenge a voter’s eligibility.

“None of those legal processes were employed during this election cycle,” Logan says. “So we didn’t see any legal effort to challenge the eligibility of voters prior to the election. We didn’t see any challenges on Election Day. And I think that sort of goes to the point that there’s nothing to back up those allegations.”

Padilla, a Democrat who many political observers believe has aspirations for higher office, challenged Trump to show proof.

“If you have evidence, please bring it forward,” Padilla told NPR.