Obama says more work to do

Barack Obama, with his ninth straight win over Hillary Clinton in the Wisconsin primary, told supporters in Houston that while he's on a roll, he needs their help to secure the nomination, then win the White House.

"The change we seek is still months and miles away and we need the good people of Texas to help us get there," he said, pre-empting Clinton's speech in Ohio.

He said his string of victories shows that the desire for change and a different kind of politics is real and deep. "My faith in the American people has been vindicated," he said.