Democratic and Republican candidates now focus on two big delegate prizes -- Ohio and Texas, which conduct their primary elections March 4.

Obama also won the Democratic primary Tuesday in Wisconsin. Obama has emerged as the front-runner after a neck-and-neck battle with Sen. Hillary Clinton, D-N.Y., on Super Tuesday.

"The change we seek is still months and miles away," Obama said Tuesday on a campaign stop in Texas.

In the Republican race, the Wisconsin win gives McCain at least 13 more delegates -- 24 more delegates are to be awarded to the winner of each congressional district, CNN reported. The remaining three GOP delegates are unpledged Republican National Committee members.

McCain also bested former Arkansas Gov. Mike Huckabee in Washington state's primary, where 19 delegates were up for grabs. Eighteen delegates were awarded earlier in the state's caucuses.