Updated

The longtime caretakers of a Mojave Desert cross that led to a Supreme Court case are vowing to replace the memorial, which was stolen less than two weeks after the high court allowed it to remain standing.

The 7-foot-tall metal cross in a 75-year-old war memorial was ripped down and stolen Sunday night from its place in the Mojave Desert, according to federal officials.

The Veterans of Foreign War has promised that the memorial -- an incarnation of which was first erected in 1934 to honor soldiers killed in World War I -- will be rebuilt.

"This is an outrage, akin to desecrating people's graves," said Kelly Shackelford, president of the Liberty Institute, which represents the caretakers of the Mojave Desert War Memorial. "It's a disgraceful attack on the selfless sacrifice of our veterans. We will not rest until this memorial is re-installed."

The National Park Service says someone cut the metal bolts holding the metal-pipe cross to the top of the memorial's Sunrise Rock and made off with it Sunday night or before dawn on Monday.

Authorities had no immediate motive for the theft but National Park Service officials are considering a range of ideas from scrap metal scavengers to people "with an interest in the case," said Park Service spokeswoman Linda Slater.

The American Civil Liberties Union of Southern California had sued over the cross on federal land, saying it was a violation of the constitutional separation of church and state.

Veterans groups were outraged by the theft.

"The American Legion expects whoever is responsible for this vile act to be brought to justice," said Clarence Hill, the group's national commander. "While the memorial has been attacked, the fight will continue to ensure that veterans memorials will remain sacrosanct."

"To think anyone can rationalize the desecration of a war memorial is sickening, and for them to believe they won't be apprehended is very naïve," said VFW National Commander Thomas J. Tradewell Sr.

The cross has been covered with a tarp or a wooden box since 2002 by a court order to avoid violating federal law mandating the separation of church and state. The 75-year-old monument was the target of a longstanding legal challenge from the ACLU, which charged that the cross is a religious symbol that shouldn't be allowed on public land. The U.S. Supreme Court last month refused to order that it be torn down in a 5-4 decision.

But the Supreme Court also referred the case back to a lower court for further review, forcing the caretakers to continue covering the cross with a pine box. Maintenance workers noticed on Saturday that the box had been removed, and were preparing to restore it Monday morning when they found that the entire cross was missing.

Park officials said the box has been removed "several times" in the past and covered with graffiti at least once -- but that no one had ever before attempted to physically remove the cross itself.

The Liberty Institute is now offering a $25,000 reward for information leading to the arrest and conviction in the case, and the National Park Service has established a tip hotline seeking information leading to the recovery of the cross. Anyone with information is asked to contact the Park Service at (760) 252-6120.

It's not clear if a replacement cross will be permitted. A park service spokeswoman says officials are waiting on word from the Justice Department.

The Associated Press contributed to this report.