U.S. Sen. Ted Cruz of Texas is leading the Republican field, according to a Wall Street Journal/NBC News poll released Wednesday. The poll revealed some GOP voters are beginning to sour on billionaire businessman Donald Trump, who had previously dominated the poll with a 13-point lead over Cruz.

In the new poll, Cruz held the backing of 28 percent of Republican voters nationwide, followed by Trump with 26 percent, Florida Sen. Marco Rubio with 17 percent, Ohio Gov. John Kasich at 11 percent, retired neurosurgeon Ben Carson with 10 percent and Florida Gov. Jeb Bush with 4 percent.

RTX27EQQ Republican presidential candidate Sen. Ted Cruz, R-Texas, responds to a threatened lawsuit over campaign ads from GOP rival Donald Trump during a news conference in Seneca, South Carolina, Feb. 17, 2016. Photo: Reuters

"The sound you're hearing is the sound of screams coming from Washington, D.C.," Cruz told supporters at a rally in Spartanburg, South Carolina, Wednesday afternoon, CNN reported. "But what's happening nationally is indicative of the stakes in this race." 

However, it was not clear whether the results of the poll signal that support for Trump is slipping, or whether this was a passing phase. 

RTX277RF U.S. Republican presidential candidate Senator Ted Cruz (R-TX) is pictured at a campaign event on the USS Yorktown in Mount Pleasant, South Carolina Feb. 16, 2016. Photo: Reuters

“When you see a number this different, it means you might be right on top of a shift in the campaign,” said Bill McInturff, a GOP pollster who conducted the survey with Democratic pollster Fred Yang, the Wall Street Journal reported. “What you don’t know yet is if the change is going to take place or if it is a momentary pause before the numbers snap back into place.”  

The survey was conducted Feb. 14-16 among 400 registered voters who said they would participate in a GOP primary. It had a margin of error of plus or minus 4.9 percentage points.