A federal judge has declared in a ruling that applies only to death certificates that Ohio’s ban on equal marriage is unconstitutional.

According to the Associated Press, Judge Timothy Black’s decision orders state officials to recognise the presence of such unions on death certificates.

Although his ruling applies narrowly, his statements about the same-sex marriage ban in Ohio are sweeping and expected to incite further litigation challenging the law.

In his decision on Monday, the judge stated that “once you get married lawfully in one state, another state cannot summarily take your marriage away.”

He said the US Constitution recognises the right to remain married as a fundamental liberty.

Judge Black’s decision relates to a lawsuit filed in July by two gay Ohio men whose spouses recently died and wanted to be recognised on their death certificates as married.

Last week, the Supreme Court in New Mexico legalised equal marriage, declaring it is unconstitutional to deny marriage rights for same-sex couples in the state.