Jeremy Hughes, a Nevada strategist for Marco Rubio, said he was hearing about extensive problems at caucus sites across the state.
At his own caucus site in Clark County, he said volunteers were checking in voters to caucus without checking their IDs, including one member of the Rubio team. Hughes said he reported the violations to Sue Lowden, the former chairwoman of the Nevada Republican Party who happened to be at that caucus site, and she reprimanded the woman.
"We assume that situation was resolved," said Hughes, who said he was unable to find a site manager to report the violations to.
"Trying to to catch all the fraud that's going on here would like trying to plug all the holes in the Titanic," Hughes said in a telephone interview as he left his caucus site. "You fix one and another one bursts."
Hughes later said he is confident now after checking across the state that the Republican National Committee is chasing down the problems that have occurred -- largely due to confusion, complex procedures and a higher than expected turnout. He added he is now confident that there is no fraud occurring, and that the party is on top of the problems.
The Nevada Republican Party, tweeting from its official account, weighed in.
"There have been no official reports of voting irregularities or violations," Nevada GOP tweeted.
Amid reports of caucus sites unprepared for high turnout and individuals casting multiple ballots, Nevada reporter Jon Ralston offered his own commentary and got a quick reaction from an official.
Nevada reporter Karen Castro reported one site ran out of ballots and left would-be caucus-goers waiting for a resupply.
Complicating matters further, an anchor for Las Vegas called it a "moment of chaos" when Trump arrived at one caucus site.
Gambling magnate and major GOP donor Sheldon Adelson showed up to cast a ballot to some fanfare, Alexandra Berzon tweeted.
A GOP source says they are getting reports of problems at sites across the state and complained the state was not prepared for the high turnout.
Another source told CNN that ballots were running out at a polling station in Summerlin.
CNN affiliate KLAS in Las Vegas said
that "some caucus sites have run out of ballots. The RNC says more are being delivered."
CORRECTION: An earlier version of this story misspelled Sue Lowden's name.