Judges in San Francisco said the patriotic statement is illegal because it violated the basic separation of church and state as ordered by the US Constitution.

I pledge allegiance to the flag of the United States of America, and to the Republic for which it stands, one nation under God, indivisible, with liberty and justice for all

Pledge of Allegiance

Their decision was denounced as "ridiculous" by President George W Bush and "just nuts" by Senate majority leader Tom Daschle.

The Department of Justice is now examining how to overturn the verdict and the Senate voted 99-0 to show its support for the pledge, and instruct its lawyer to work to keep the wording as it is.

In 1954 President Dwight Eisenhower allowed the adding of the words "under God" to the oath which has been recited by generations of American schoolchildren.

The Ninth Circuit Court of Appeals in San Francisco - whose rulings cover nine western states - is allowing several months for appeals and its decision will not take immediate effect.

The judges - in a 2-1 verdict - overturned a lower court ruling that dismissed a case against the pledge brought by the father of a schoolgirl.

They wrote: "The text of the official pledge, codified in federal law, impermissibly takes a position with respect to the purely religious question of the existence and identity of God.

"A profession that we are a nation 'under God' is identical... to a profession that we are a nation 'under Jesus,' a nation 'under Vishnu,' a nation 'under Zeus,' or a nation 'under no god'," it said.

'Unacceptable choice'

The Department of Justice had argued that the phrase "one nation under God" had minimal religious content.

But the appeals court ruled that an atheist or a follower of some religions could see it as an endorsement of monotheism.

And although students could not be compelled to take the pledge, the judges said young children would be faced with an "unacceptable choice between participating and protesting" if it was recited in a classroom.

But the dissenting judge, Ferdinand Fernandez, said other institutions could be affected by his colleagues' logic, including the singing of "God Bless America" and "America the Beautiful" as well as the US dollar, which has "In God We Trust" printed on every banknote.

In Washington DC, about 100 members of the House of Representatives stood on the steps of the Capitol and sang "God Bless America" after reciting the pledge, with the "under God" phrase.

If the ruling does stand, it will affect schools in the states of Alaska, Arizona, California, Hawaii, Idaho, Montana, Nevada, Oregon and Washington.