Mitt Romney won't participate in the n

next week, his campaign said Monday.

The announcement, which did not come as a surprise, could well lead to the cancellation of what has been the last scheduled debate of the Republican presidential primary campaign. Debate sponsors said they wanted to review the latest development before making any comment.

Romney's statement didn't leave any wiggle room about his decision not to be in Portland next Monday.

"Gov. Romney will not be participating since he will be in Illinois for its March 20 primary," campaign spokeswoman Andrea Saul said in a statement. "We look forward to campaigning in Oregon before the May 15 primary."

There was no immediate reaction from the campaigns of the three other GOP candidates – former Pennsylvania Sen. Rick Santorum, Texas Rep. Ron Paul and former House Speaker Newt Gingrich.

Oregon Republican Chairman Allen Alley had said last week it's possible the debate could proceed even if Romney dropped out. But it's not clear if the other three would want to proceed on those terms or if the Public Broadcasting Service would still want to devote 90 minutes of prime time to the debate.

"We have to review this development with our partners before making any comment," said Greg Leo, chief of staff of the Oregon Republican Party. The state GOP, Oregon Public Broadcasting and The Washington Times are sponsors of the debate, which was to be carried on public television and National Public Radio.

The sponsors had been aware from the beginning that the debate could get cancelled at the last minute. One of the major reasons that they planned to hold it inside the OPB studios was to avoid the costs of renting a space that might not wind up being used.

The candidates have debated about 20 times during the campaign season and several Republican officials worried that the debates have pushed Romney – the front-runner in the delegate count – to the right and hurt his chances of defeating President Obama in the fall.

Romney also led the move to cancel a March 1 debate in Atlanta that was to be carried on CNN. The candidates last had a formal debate on Feb. 22 in Arizona. In addition, Romney, Santorum and Gingrich also participated in a March 3 forum on Fox News that was moderated by former Arkansas Gov. Mike Huckabee.

The planned Portland debate

, who said in January that he didn't want a presidential debate held in the city. He said the police overtime budget had been exceeded because of the Occupy Portland protests and he didn't want the city to take on the security costs the debate would incur.

Debate sponsors proceeded anyway, and they rebuffed Adams' request to move the event from the OPB studies to a venue closer to the airport that would reduce security costs.

Charles Pope of The Oregonian staff contributed to this report.

--Jeff Mapes

