President Trump spent a portion of his Saturday focused on a special election in the suburbs of northern Los Angeles County, attacking a decision to add an in-person voting center there in a series of misleading tweets.

The race is between Democratic state assemblywoman Christy Smith and Republican businessman and ex-Navy pilot Mike Garcia. They are seeking to fill a seat left vacant by former congresswoman Katie Hill (D), who resigned in the fall. Whoever wins on Tuesday will hold the California seat through the end of the year. Regardless of the outcome, the two will face each other again in November for a full two-year term.

Because of the coronavirus, voters were encouraged to mail in ballots, with every voter receiving a prestamped ballot to fill out and return. But a limited number of in-person polling places were long planned to be open, and one was added recently in Lancaster.

“Governor @GavinNewsom of California won’t let restaurants, beaches and stores open, but he installs a voting both system in a highly Democrat area (supposed to be mail in ballots only) because our great candidate, @MikeGarcia2020, is winning by a lot. CA25 Rigged Election!” Trump tweeted Saturday.

He also tweeted: “So in California, the Democrats, who fought like crazy to get all mail in only ballots, and succeeded, have just opened a voting booth in the most Democrat area in the State. They are trying to steal another election. It’s all rigged out there. These votes must not count. SCAM!”

Lancaster, like the rest of the 25th district. has been trending more Democratic. However, it is not the most Democratic area in California, as Trump suggests. In the state legislature, Lancaster is represented by two Republicans, and the mayor, Rex Parris, is a Republican.

Democrats had raised concerns that Lancaster, which has a large African-American population, didn’t have an in-person voting place, arguing it disenfranchised voters who were more likely to vote in person on Election Day. Parris supported opening the voting center in Lancaster.

In a normal election, California’s 25th district would have around 1,000 polling locations available, a spokesman for Smith’s campaign told The Washington Post. On Tuesday, because of the coronavirus, there will be 13, including Lancaster, he said.

On Saturday, Smith released a statement commending the decision to add a polling place in Lancaster. She also responded to Trump’s tweets, writing, “In CA we believe in expansive voting rights. We also believe in states’ rights. Why don’t you Mr. President?”

Garcia echoed the president’s rhetoric on Twitter, accusing Smith and “her liberal Dem allies” of being “desperate and trying to change the rules to steal an election. We can’t let them succeed!!”

Mail in ballots have been an option in California elections long before the threat of spreading the coronavirus, so that is not unique to this special election. Republicans in the district have historically been more likely than Democrats to mail in ballots, while Democrats have tended to vote more heavily on Election Day.

More than one in four ballots have been returned, which is high for a special election. Of all registered Republicans, 39 percent have turned in ballots, of registered Democrats, 25 percent and of registered independents 19 percent, according to a tracker of ballot returns in California.

During the coronavirus outbreak, most election officials of both parties across the country have recommended keeping in-person polling places open in addition to expanded mail balloting to accommodate those unable or unaccustomed to voting by mail.

Trump has previously criticized the expansion of mailing ballots.

“I think that mail-in voting is a terrible thing,” Trump said in early April. “I think if you vote, you should go. ...There’s a lot of dishonesty going on with mail-in voting, mail-in ballots.”

Amy Gardner contributed to this report.