FORT MYERS, Fla. -- A statewide voter intimidation effort is targeting registered Republicans, election officials warned on Monday. Several Southwest Florida residents have received bogus letters claiming they are ineligible to vote.

The Florida Secretary of State's Office is now investigating these letters, which appear to be sent from Seattle, WA. At least five residents in Collier County and another in Lee have received the letters.

At first glance the letters appear legitimate. One letter sent to a Collier County resident, has the name and logo of the county elections supervisor, though it's not quite the same.

The letters claim that the county has received information regarding the person's citizenship status. It says they have 15 days to respond or else their names will be removed from the voter rolls. Similar to the letters sent to suspected non-citizens earlier this year.

Election officials say any legitimate letter from them would be certified, as per federal law. And the letter recipient would have 30 days to respond, not 15.

Tim Durham with the Collier County Elections office says this is an overt and clumsy attempt at voter intimidation.

Click here to read the letter that's circulating.