GOP front-runner Donald TrumpDonald John TrumpClinton takes swipe at 'false equivalency' in media coverage of 2016 election Trump asked Netanyahu if he actually cares about peace: report Official: Trump to urge North Korea to dismantle nuclear program in return for sanctions relief MORE has bumped Ted CruzRafael (Ted) Edward CruzCruz's Dem challenger slams Time piece praising Trump Race for Republican Speaker rare chance to unify party for election 32 male senators back Senate women's calls to change harassment rules MORE from the lead in Iowa just a month before the first-in-the-nation caucuses, according to a new online poll.

Trump, with 39 percent, has a 5-point lead among likely Republican caucus-goers over Cruz, a CBS News “Battleground Tracker” poll released Sunday morning shows. Marco RubioMarco Antonio RubioGOP Senate candidates trade barbs in brutal Indiana primary Students gather outside White House after walkout to protest gun violence Overnight Energy: Senate confirms Bridenstine as NASA chief | Watchdog probes Pruitt’s use of security detail | Emails shine light on EPA science policy changes MORE is in third place, with 13 percent.

Pollsters found that Trump cut into Cruz’s support among Tea Partiers and evangelicals in Iowa, CBS said.

The New Hampshire race is unchanged, according to the new poll, with Trump holding a wide lead over Cruz and Rubio. John Kasich is now in fourth place, however, replacing Gov. Chris Christie.

Trump also still holds a double-digit lead in South Carolina, CBS found.

The online polling firm YouGov conducted the poll for CBS. It has a 7.2 percent margin of error in Iowa, 6.8 percent margin of error in New Hampshire and 5.7 percent margin of error in South Carolina.