The U.S. Supreme Court has refused to hear a case that challenges the use of God's name on U.S. currency.

The court on Monday refused to hear an appeal from Michael Newdow, an atheist, who says government references to God are unconstitutional and infringe on his beliefs.

Newdow's case was an appeal of an earlier ruling by San Francisco's 9th Circuit Court of Appeals.

That court found the phrase to be ceremonial and patriotic, writing it "has nothing whatsoever to do with the establishment of religion."

The phrase "In God We Trust" has been America's official motto since 1956. It was first put on U.S coins in the 1860s and on paper currency in 1957.