Of the nearly 4,000 letters mailed this month by Secretary of State Scott Gessler to suspected noncitizens — asking that they prove they are eligible to vote or remove themselves from the voter rolls — 12.45 percent went to Republicans, prompting critics to again question whether the effort is politically motivated.

Gessler, a Republican, has strongly denied the allegation that his effort to block noncitizens from voting is intended to keep left-leaning voters from going to the polls in November.

Of the 3,903 letters mailed, the largest number — 1,794 — was sent to unaffiliated voters, while 1,566 went to Democrats and 486 to Republicans. The other 57 went to other parties.

As of Aug. 1, Colorado's registered voters were 35 percent unaffiliated, 33 percent Republicans and 32 percent Democrats.

"It makes me suspect, and it should make the people of the state suspect, what his true motivations are," state Rep. Crisanta Duran, a Denver Democrat, said, referring to Gessler.

The numbers were first reported Monday by The Associated Press.