(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.



The interruption will cause Obama to cancel Thursday events in Madison, Wisconsin and Des Moines, Iowa. He will do an event in Indianapolis, Indiana, Thursday morning before leaving and will return to the campaign Saturday, Gibbs said.



Michelle Obama will fill in for her husband on Friday at previously scheduled events in Columbus and Akron, Ohio, his campaign said.



Obama speaks about his grandmother often on the stump, describing her as an integral figure in his youth who struggled against the glass ceiling in to make a better life for him.



"She's the one who put off buying a new car or a new dress for herself so that I could have a better life," he said in his acceptance speech at the Democratic National Convention in August. "She poured everything she had into me. And although she can no longer travel, I know that she's watching tonight, and that tonight is her night as well."



He and his family traveled to Hawaii in August to visit her.



The Obama team made the announcement after a busy day of trading attacks with Sen. John McCain on the Democratic presidential hopeful's readiness for office.



Monday also marked the first time that Obama appeared with Sen. Hillary Clinton during the general election season.



Clinton went to Florida, a state she won in the primary but whose delegates she could not claim, to urge her supporters to turn out for Obama on Election Day.



Clinton called Orlando and central Florida "the battleground of the battleground" and practically begged the crowd to vote early.



"We are 15 days from the finish line and we cannot falter, we cannot stop, we cannot take a single vote for granted," Clinton said Monday. "I am asking you to work as hard for Barack as you worked for me. If you made phone calls for me, make them for Barack. If you walked streets for me, make them for Barack. If you talked to your friends and neighbors for me, do it again for Barack. We cannot risk four more years of the same failed Republican policies."



Earlier in the day, McCain told a crowd in Belton, Missouri, that the next president "won't have time to get used to the office."



He was addressing comments made Sunday by Obama's running mate, Sen. Joe Biden, in which he said Obama would be tested within the first six months of his presidency.



"We don't want a president who invites testing from the world at a time when our economy is in crisis and Americans are already fighting in two wars," McCain said. "What is more troubling is that Sen. Biden told their campaign donors that when that crisis hits, they would have to stand with them because it wouldn't be apparent Sen. Obama would have the right response.



The Obama-Biden campaign released a pre-emptive response after reading McCain's scheduled remarks.



"With our nation facing two wars and 21st century threats abroad, Sen. Biden referenced the simple fact that history shows presidents face challenges from day one," Obama spokesman David Wade said. "After eight years of a failed foreign policy, we need Barack Obama's good judgment and steady leadership, not the erratic and ideological Bush-McCain approach that has set back our security and standing in the world."



Earlier Monday, Obama denounced the "say-anything
Where was Obama on Thursday? What day's events are canceled? Who said Obama would be tested with an early crisis? Who urged Floridians to back Obama? Who will be tested with an early crises? What was Clinton urging Florida to do? What happened to the rest of the Thursday events? When did Obama leave the campaign trail? Who will be tested with early crisis? Who urges Floridians to back Obama?
Hawaii, break from campaigning Sen. Joe Biden, Clinton Obama turn out for Obama on Election Day. take a break from campaigning Thursday Obama Clinton
question: Where was Obama on Thursday?, answer: Hawaii, | question: What day's events are canceled?, answer: break from campaigning | question: Who said Obama would be tested with an early crisis?, answer: Sen. Joe Biden, | question: Who urged Floridians to back Obama?, answer: Clinton | question: Who will be tested with an early crises?, answer: Obama | question: What was Clinton urging Florida to do?, answer: turn out for Obama on Election Day. | question: What happened to the rest of the Thursday events?, answer: take a break from campaigning | question: When did Obama leave the campaign trail?, answer: Thursday | question: Who will be tested with early crisis?, answer: Obama | question: Who urges Floridians to back Obama?, answer: Clinton