A federal judge has struck down the US state of Wisconsin’s same-sex marriage ban.

The ACLU filed the lawsuit in February on behalf of eight gay and lesbian couples, stating that they are denied equal treatment afforded to straight, married couples under the law.

US District Judge Barbara Crabb struck down the ban on Friday, stating that gay couples “are entitled to the same treatment as any heterosexual couple.”

Same-sex couples began to marry within minutes of the state’s ban being struck down in some counties.

Attorney General J B Van Hollen said the law banning same-sex marriage, written into the state constitution “remains in force”.

“While today’s decision is a setback, we’ll continue to defend the constitutionality of our traditional marriage laws and the constitutional amendment, which was overwhelmingly approved by voters,” Van Hollen said. “I will appeal.”

The Attorney General last week made an unusual request for a federal judge to stay any ruling she may make to strike down the state’s ban on same-sex marriage.

The American Civil Liberties Union (ACLU) previously asked Judge Crabb to suspend the ban via a preliminary injunction as part of its legal challenge– a request she declined.