Obama: 'A lot more work to do'
President Obama told supporters his win "wasn't fate and it wasn't an accident".
In an email sent to people signed up to his campaign, he said: "Friend, I'm about to go speak to the crowd here in Chicago, but I wanted to thank you first.
"I want you to know that this wasn't fate, and it wasn't an accident. You made this happen.
"You organised yourselves block by block. You took ownership of this campaign five and ten dollars at a time. And when it wasn't easy, you pressed forward.
"I will spend the rest of my presidency honouring your support, and doing what I can to finish what we started.
"But I want you to take real pride, as I do, in how we got the chance in the first place.
"Today is the clearest proof yet that, against the odds, ordinary Americans can overcome powerful interests.
"There's a lot more work to do.
"But for right now: Thank you.