"Senator Obama's grandmother, Madelyn Dunham, has always been one of the most important people in his life. Along with his mother and his grandfather, she raised him in Hawaii from the time he was born until the moment he left for college. As he said at the Democratic Convention, she poured everything she had into him," said Gibbs in a statement.
"Recently, his Grandmother has become ill, and in the last few weeks, her health has deteriorated to the point where her situation is very serious. It is for that reason that Senator Obama has decided to change his schedule on Thursday and Friday so that he can see her and spend some time with her."
The campaign is set to resume on Saturday.
Madelyn Dunham, 85, helped raise Obama, 47. In a campaign ad earlier this year, the White House aspirant described Dunham as the daughter of a Midwest oil company clerk who "taught me values straight from the Kansas heartland."
Michelle Obama to CampaignObama's Thursday and Friday schedule had him headed to the battleground states of Wisconsin and Ohio. Polls show him as being ahead in both states.
Obama campaign spokeswoman Jen Psaki said that on Friday Michelle Obama, the candidate's wife, would represent her husband in Ohio. The national election is in two weeks.
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