SANTA FE, N.M. — New Mexico election officials have witnessed a surge in online voter registration activity after 460,000 invitation postcards were mailed to residents who appear to be eligible to vote but have not registered.

The New Mexico Secretary of State’s Office saw a 10-fold increase in weekly online voter registration and updates to voter records. Elections Director Kari Fresquez said that online registrations and updates increased to 10,849 during the week ending on Saturday, from 1,189 the previous week.

The Secretary of State’s Office sent out postcards invitations on Sept. 19 to a list of addresses generated by the Electronic Registration Information Center, which checked driver’s license records against voter registration rolls to locate likely unregistered voters.

The nonprofit center helps 21 member states improve the accuracy of voter registration lists. New Mexico joined the center in July. The deadline to register for fall elections in New Mexico is Oct. 11, when absentee balloting begins.

State Rep. Nora Espinoza, the Republican candidate running to succeed Secretary of State Brad Winter, has criticized the voter registration mailing, raising concerns that postcards went out to noncitizens who may be encouraged to attempt to register and vote.

Rod Adair, a spokesman for Espinoza, said the Secretary of State’s Office should be focused on purging voter rolls of inaccurate entries before sending out registration mailings.

“The cards are confusing. It says, ‘Register to vote,'” Adair said. “There are lots of people who do not follow all instruction and the potential for fraud is huge.”

Fresquez acknowledged that postcards were received by some people who are not eligible to vote, while noting that basic registration requirements — including U.S. citizenship — are clearly stated on the cards and that all registration applications are vetted by an online registration system or local county clerks or both.

“It’s just a postcard,” Fresquez said. “It’s not an automatic registration.”

Fresquez said that there is no easy way to filter out noncitizens from the mailing list because New Mexico Motor Vehicle Division records do not flag noncitizens.

The $114,000 mailing was paid for the by the Pew Charitable Trusts, which helped create the Electronic Registration Information Center in 2012, and by county clerks across the New Mexico.

The Democratic nominee for secretary of state, Bernalillo County Clerk Maggie Toulouse Oliver, supports the new state efforts to contact eligible, unregistered voters.

“There is really not any harm because they’ll have to go through the process of the online registration portal,” she said. “If someone is a noncitizen and they attempt to register, that’s a crime and that can affect a potential path to citizenship. We should have a zero-tolerance policy.”

The number of registered voters in New Mexico increased by nearly 50,000 between January and August to 1,247,911. Registration increases among Democrats have outpaced those of Republicans and unaffiliated voters.