The US Supreme Court has refused to block the removal of a biblical display from Alabama's state judicial building, rejecting a last-minute appeal from the state's chief justice, Roy Moore.
Civil liberties activists object to the stone
Mr Moore now has until midnight on Wednesday (0500 GMT Thursday) to comply with a federal court order to remove the monument, which is inscribed with the Ten Commandments.
But he pledged defiance, saying the decision "will not
deter me from continuing to fight for the right of our state to
acknowledge God as the moral foundation of our law," in a statement read by his spokesman.
Critics of the 2,500-kilogram (5,300-pound) granite slab say it violates the constitutional separation of church and state.
The state could face fines of up to $5,000 a day if it refuses to comply with the federal court order to remove the stone, which is nicknamed "Roy's holy rock".
The fines would double after a week.
Mr Moore, a conservative Baptist, was elected to two years ago based on a campaign pledge to install "the law God gave to Moses" in his courthouse. He has the monument installed last July, in the rotunda of the judicial building.
The Supreme Court offered no comment in its one-line order rejecting Mr Moore's appeal.
In a ruling last year, a federal court judge decided the religious monument crossed the line "between the permissible and the impermissible".
But Mr Moore has strongly resisted the calls for it to be removed, insisting that it is statement of the Christian roots of the law.
Moore was elected on a platform of installing God in court
He said last week he would defy the federal judge's order, arguing that the lower court had no power to rule on the matter.
About 30 Christians have been holding a prayer vigil in Montgomery to oppose the removal of the stone.
"We are a Godly people and the Ten Commandments represent our submission to God," said Phil Beverly, at the vigil.