OAKLAND, Calif. (AP) -- A California preacher who foretold of the world's end only to see the appointed day pass with no extraordinarily cataclysmic event has revised his apocalyptic prophecy, saying he was off by five months and the Earth actually will be obliterated on Oct. 21.

Harold Camping, who predicted that 200 million Christians would be taken to heaven Saturday before catastrophe struck the planet, apologized Monday evening for not having the dates "worked out as accurately as I could have."

He spoke to the media at the Oakland headquarters of his Family Radio International, which spent millions of dollars -- some of it from donations made by followers -- on more than 5,000 billboards and 20 RVs plastered with the Judgment Day message.

It was not the first time Camping was forced to explain when his prediction didn't come to pass. The 89-year-old retired civil engineer also prophesied the Apocalypse would come in 1994, but said later that didn't happen then because of a mathematical error.

Through chatting with a friend over what he acknowledged was a very difficult weekend, it dawned on him that instead of the biblical Rapture in which the faithful would be swept up to the heavens, May 21 had instead been a "spiritual" Judgment Day, which places the entire world under Christ's judgment, he said.

The globe will be completely destroyed in five months, he said, when the apocalypse comes. But because God's judgment and salvation were completed on Saturday, there's no point in continuing to warn people about it, so his network will now just play Christian music and programs until the final end on Oct. 21.

"We've always said May 21 was the day, but we didn't understand altogether the spiritual meaning," he said. "The fact is there is only one kind of people who will ascend into heaven ... if God has saved them they're going to be caught up."

Josh Ocasion, who works the teleprompter during Camping's live broadcasts in the group's threadbare studio sandwiched between an auto shop and a palm reader's business, said he enjoyed the production work but never fully believed the May 21 prophecy would come true.

"I thought he would show some more human decency in admitting he made a mistake," he said Monday. "We didn't really see that."

Follower Jeff Hopkins said he spent a good deal of his own retirement savings on gas money to power his car so people would see its ominous lighted sign showcasing Camping's May 21 warning. As the appointed day drew nearer, Hopkins started making the 100-mile round trip from Long Island to New York City twice a day, spending at least $15 on gas each trip.

"I've been mocked and scoffed and cursed at and I've been through a lot with this lighted sign on top of my car," said Hopkins, 52, a former television producer who lives in Great River, NY. "I was doing what I've been instructed to do through the Bible, but now I've been stymied. It's like getting slapped in the face."

Camping's hands shook slightly as he pinned his microphone to his lapel, and as he clutched a worn Bible he spoke in a quivery monotone about some listeners' earthly concerns after giving away possessions in expectation of the Rapture.

Family Radio would never tell anyone what they should do with their belongings, and those who had fewer would cope, Camping said.

"We're not in the business of financial advice," he said. "We're in the business of telling people there's someone who you can maybe talk to, maybe pray to, and that's God."

But he also said that he wouldn't give away all his possessions ahead of Oct 21.

"I still have to live in a house, I still have to drive a car," he said. "What would be the value of that? If it is Judgment Day why would I give it away?"

Apocalyptic thinking has always been part of American religious life and popular culture. Teachings about the end of the world vary dramatically - even within faith traditions - about how they will occur.

Still, the overwhelming majority of Christians reject the idea that the exact date or time of Jesus' return can be predicted.

Tim LaHaye, co-author of the best-selling "Left Behind" novels about the end times, recently called Camping's prediction "not only bizarre but 100 percent wrong!" He cited the Bible verse Matthew 24:36, "but about that day or hour no one knows" except God.

Camping offered no clues about Family Radio's finances Monday, saying he could not estimate how much had been spent advertising his prediction nor how much money the nonprofit had taken in as a result. In 2009, the nonprofit reported in IRS filings that it received $18.3 million in donations, and had assets of more than $104 million, including $34 million in stocks or other publicly traded securities.

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Associated Press writer Tom Breen in Raleigh, N.C., and Videographer Ted Shaffrey and AP Religion Writer Rachel Zoll in New York, contributed to this report.