WILLIAMSTOWN, Ky. -- A group opposed to a new Noah's ark attraction in Kentucky says it is warning hundreds of public schools against visiting the Ark Encounter.

The Freedom From Religion Foundation said ark field trips would expose children to religious proselytizing in violation of the constitutional separation of church and state.

Foundation co-president Annie Laurie Gaylor told the Lexington Herald-Leader that warning letters went to more than 1,000 school districts in Kentucky, Tennessee, Ohio, Indiana and West Virginia.

Kentucky Education Commissioner Stephen Pruitt sent a message to school districts Monday in response saying that neither outside groups nor state education officials should dictate field trip selection. A school's site-based decision making council approves trips.

The Madison, Wisconsin-based group said it heard from parents concerned their districts will organize trips to the ark.

The Ark Encounter project, which was created by Answers in Genesis -- the same Christian organization that runs the Petersburg Creation Museum -- has attracted attention and controversy in equal measure since its inception. It's grand opening was Thursday, a date chosen to reflect Genesis 7:7, the Bible verse describes Noah and his family entering the ark for the first time.

Answers in Genesis said it believes the ark will be the biggest timber frame structure in the world and expects to see 1.4 million to 2.2 million people each year.