WISCONSIN (CBS 58) -- The ACLU of Wisconsin says they filed a petition Thursday, asking the state Supreme Court to declare the practice of honoring ICE detainers at county jails illegal. 

The civil rights group says an ICE detainer is a request made to local sheriffs to hold someone for an additional 48 hours past their release dates so that ICE can arrest and deport them.

The lawsuit, filed on behalf of immigrant rights group Voces de la Frontera, targets jails in five state sheriff's offices -- Walworth, Brown, Kenosha, Sauk, and Marathon. 

"The lawsuit contends that honoring an ICE detainer constitutes an arrest," the ACLU says. "And Wisconsin law enforcement does not have the authority to make arrests based solely on ICE's civil administrative 'warrants.'"

“We believe that state and local law enforcement are overstepping their authority under Wisconsin law by honoring ICE detainers, regardless of whether they operate under a 287(g) agreement with ICE that purports to delegate certain immigration enforcement powers to local law enforcement,” said Tim Muth, a senior staff attorney with the ACLU of Wisconsin. “This is an important issue that must be addressed quickly, as our immigrant neighbors are living in fear and constantly at risk of being unlawfully held and apprehended by ICE.”