Roughly 30,000 non-US citizens in Colorado were sent postcards encouraging them to vote.

Secretary of State Jena Griswold’s office sent the postcards “mistakenly” on Sept 27 “after department employees compared a list of names of 102,000 people provided by the Electronic Registration Information Center to a database of Colorado residents issued driver’s licenses,” Fox News reports.

Non-US citizens with special licenses are included in Colorado’s Department of Revenue’s driver’s license list, but did not make a formal distinction that said that those with licenses could not vote.

“Griswold’s office said in a statement that the postcards were mailed Sept. 27. The error happened after department employees compared a list of names of 102,000 people provided by the Electronic Registration Information Center, a bipartisan, multistate organization devoted to voter registration, to a database of Colorado residents issued driver’s licenses,” AP reports.

The letter, sent in English and Spanish, says that US citizens to register to vote. They were also given instructions on how to register to vote, though they were not given US registration votes.

Griswold has since sent notices to the 30,000 people who are not citizens that they will not be able to vote. More efforts will also be made to ensure that another similar mistake does not happen.

Colorado’s Republican Party Chair Kristi Burton Brown condemned Griswold’s error, saying in a statement: “Jena Griswold continues to make easily avoidable errors just before ballots go out” she said.

Griswold will face Republican Pam Anderson, who said in 2021 that she wanted to “restore trust in” elections.

“I’ve been increasingly concerned about the hyper-partisan nature of the rhetoric both around elections and the office of secretary of state and feel we need to return to a trusted professional in that office. I feel I can help inform the voters on how all of this works and help to move the ball forward on the outstanding election system we have here Colorado,” she said.