San Francisco - Democratic candidate Barack Obama was visiting his ailing grandmother in Hawaii on Friday, and told reporters he feared that the woman who raised him after his mother died would not live until election day.

"Without going through the details too much, she's gravely ill," Obama told ABC's Good Morning America on Friday. "You know, we weren't sure, and I'm still not sure, whether she makes it to election day. We're all praying and we hope she does."

Obama flew in to the island state Thursday night and went straight to visit Madelyn Dunham, 85, at the apartment complex where he grew up and where she still lives.

"I want to give her a kiss and a hug," Obama told ABC. "And then we're going to find out what chores I can do, because I'm sure there's been some stuff that's been left undone."

Obama said Thursday he decided to take a break from the campaign to avoid repeating the tragic error of failing to make it back to see his mother, Dunham's daughter, Stanley Ann Dunham Soetoro, before she died of cancer at the young age of 52.

"(We) got there too late," he said in an interview with CBS. "We knew she wasn't doing well. But, you know, the diagnosis was such where we thought we had a little more time and we didn't. And so I want to make sure that I don't - I don't make the same mistake twice."

Obama has often paid tribute to Dunham, and mentioned her decisive influence on him when he accepted the Democratic nomination in September.

On Thursday he again explained their special connection.

"My mother was a single mom, so she raised me with the help of my grandparents. And so my grandmother, my grandfather, my mom, they're really the people who - who took care of me all throughout my childhood."

"My grandmother's the last one left. She has really been the rock of the family, the foundation of the family. Whatever strength, discipline that I have, it comes from her."

Asked whether he feared the impact of his break on the election campaign, Obama said the electorate would understand.

"I think most people understand that if you're not caring for your family, then you're probably not the kind of person who's going to be caring for other people," he said.

Obama was due back to campaign in the battleground state of Nevada on Saturday. In his absence his wife Michelle was campaigning in the closely contested state of Ohio.

Independent analysts say that the trip could even play as an advantage to Obama, especially among seniors in key states like Florida. (dpa)