Dozens of voters in Pueblo County, Colorado have claimed electronic voting machines have changed their votes for Mitt Romney to votes for President Barack Obama.

The Pueblo County Republican Party has asked the Colorado Secretary of State's office to investigate the matter.

A voter told KRDO Newschannel 13 that a checkmark appeared next to Obama's name after she cast her vote for Romney. 

"I wonder where my vote really counted," she stated.

Pueblo County Clerk and Recorder Gilbert Ortiz admitted he was aware of "fewer than ten instances" of votes being switched and conceded such errors have occurred since the county has used the electronic voting machines in 2006. He blamed those changes on human error. 

Gilbert said voters had several chances to check their ballot before submitting it, but Pueblo Republican Chair Becky Mizel said the county's clerk office should, "at the very minimum," place a note on the door of polling places informing voters to lookout for potential problems with the voting machines.

Last week, the Republican National Committee sent letters to six states, asking them to more closely monitor electronic voting machines -- and to re-calibrate them -- on Election Day. Colorado was one of those six states.