A lawsuit has been filed in the US state of North Dakota, challenging the state’s ban on same-sex marriage.

Seven same-sex couples in the state filed the lawsuit on Friday in federal court, meaning there are now no states in the US with unchallenged same-sex marriage bans.

Attorney General Wayne Stenehjem said in a statement on Friday that “Ultimately, only the Supreme Court can determine whether North Dakota’s enactment is constitutional or not.”

Voters in North Dakota approved a ban on same-sex marriage back in 2004, with 73%.

As this is the last state to have its ban challenged in court, some have said the lawsuit may be largely symbolic, as challenges in other states may make their way through courts sooner.

South Dakota was the last state with a legal challenge to a ban on same-sex marriage, as six couples filed a lawsuit there at the end of last week.

Earlier on Friday the state of Wisconsin had its same-sex marriage ban struck down by a federal judge who deemed in unconstitutional. 

Wisconsin Attorney General J B Van Hollen shortly afterwards announced that he was seeking an emergency stay to stop same-sex couples from marrying there.