U.S. Republican presidential candidate Rick Santorum is campaigning in Texas Wednesday, one day after winning the nominating contests in three states.

Texas is a key prize for the candidates, and Santorum was there to round up both support and money.

The socially conservative Santorum won Tuesday's caucuses in Colorado and Minnesota and the primary in Missouri.

Santorum's win raises pressure on fellow contender Mitt Romney, and emphasizes the former Massachusetts governor's struggle to gain the support of the conservative Republican base. The victory also raises questions about Romney's front-runner status. The outcome was especially disappointing for Romney, who finished a distant third in Minnesota — behind Texas congressman Ron Paul.

Santorum, a former senator from Pennsylvania, has touted his wins as proving he is the best conservative candidate to take on President Barack Obama in the November election.

Romney told supporters Tuesday night that he still expects to be the Republican nominee.

Tuesday's shake-up in the race for the White House also dealt a blow to the former speaker of the House of Representatives, Newt Gingrich, who had previously been seen as the top alternative to Romney. Gingrich finished a distant third in Colorado and fourth in Minnesota. He was not on the ballot in Missouri.