LOS ANGELES (AP) — California’s Republican Party has acknowledged owning unofficial ballot drop boxes that state election officials say are illegal.

California election officials received reports this weekend about the boxes in Fresno, Los Angeles and Orange counties. On Sunday, the secretary of state issued a memo telling county registrars the boxes are illegal and ballots must be mailed or brought to official voting locations.

“In short, providing unauthorized, non-official vote-by-mail ballot drop boxes is prohibited by state law,” the memo said.

State GOP spokesman Hector Barajas said Monday the party owns the boxes. He declined to say how many exist and where they are located. Barajas said the state’s law governing so-called ballot harvesting allows an organization to collect and return groups of ballots.

“Democrats only seem to object to ballot harvesting when someone else does it,” Barajas said.

The controversy surfaced after a regional field director for the state’s GOP in Orange County posed in a social media photo with one of the unofficial boxes and wearing a face mask supporting the congressional campaign of Michelle Steel, a county supervisor who is challenging Democratic Rep. Harley Rouda for his seat.

There was a report about a similar box at a church in the Los Angeles County community of Castaic.

In Orange County, the district attorney is investigating at least two unofficial boxes in two different cities, said Kimberly Edds, a spokeswoman for the district attorney’s office.

Neal Kelley, the county’s registrar of voters, said official drop boxes are clearly recognizable and carry the official county elections logo. He said it wasn’t clear how many voters had used unofficial boxes but after receiving reports about them he notified the state and district attorney’s office.