Opponents of the equal marriage referendum in the state of Washington on Thursday conceded that they had lost in their battle to prevent it from becoming law.

Whilst victory was announced on Wednesday morning, the full and complete result of Referendum 74 has not been officially announced, due to the state’s mail-in voting system.

It was reported, however that the bill was set to pass with 52% of the vote, with 48% of residents voting against it, reported UPI.

Joseph Backholm, chairman of Preserve Marriage Washington, which opposed the referendum, said:

“With added results showing that we have not closed the gap, it now appears clear that Referendum 74 will be narrowly approved,

“We are disappointed in losing a tough election battle on marriage by a narrow margin. But while we are disappointed, we are not defeated.”

The passing of the bill allows churches to perform same-sex marriages, as well as recognising unions between same-sex couples.

Campaign manager for Washington United for Marriage, Zach Silk, also commented on the result. He said:

“This is a historic day for Washington, a historic day for our country and, most of all, for families across the state who have dreamed of this day.”

Washington was the ninth US state to legalise equal marriage, and joined Maine and Maryland, which also legalised equal marriage at referendum on 6 November.

Meanwhile, Minnesota has voted down Amendment 1, a constitutional amendment that would have defined marriage as being a union solely between a man and a woman.

Gay couples could apply for marriage licenses as early as 6 December 2012.