(CNN)  -- Sen. Barack Obama will take a break from campaigning Thursday so he can visit his ailing grandmother in Hawaii, an Obama spokesman said Monday. Sen. Barack Obama will take a break from campaigning so he can visit his ailing grandmother. "Sen. Obama's grandmother Madelyn  Dunham has always been one of the most important people in his life," spokesman Robert Gibbs told reporters. "In the last few weeks, her health has deteriorated to the point where her situation is very serious. It is for that reason that Sen. Obama has decided to change his schedule on Thursday and Friday so that he can see her and spend some time with her," Gibbs said.
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NEW: Sen. Hillary Clinton urges Floridians to back Obama in appearance with him
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Obama will leave campaign trail Thursday after Indiana stop and return Saturday
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Rest of Thursday events canceled; Michelle Obama will stand in on Friday
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McCain references Biden comment that Obama will be tested with early crisis
He was addressing comments made Sunday by Obama's running mate, Sen. @placeholder, in which he said Obama would be tested within the first six months of his presidency.