MADISON, Wis. (AP) _ The American Civil Liberties Union has asked a federal judge to issue a preliminary injunction blocking Wisconsin's gay marriage ban while the organization's lawsuit challenging the prohibition continues.

The ACLU filed a lawsuit Feb. 3 on behalf of a group of same-sex couples arguing the ban is unconstitutional.

The organization filed a motion Thursday with U.S. District Judge Barbara Crabb seeking a preliminary injunction that would essentially invalidate the ban while the lawsuit works its way through court. In a brief accompanying the motion the ACLU argued they're entitled to a preliminary injunction because they'll likely win the lawsuit and the ban imposes irreparable harm on the same-sex couples.

The state Justice Department is defending the ban. A spokeswoman says the agency will respond to the motion in court.