LAS VEGAS - The week of chaos that followed the Iowa caucuses has prompted growing concern about problems in the next state to use that presidential nominating process, Nevada. 

Voters and campaigns have become increasingly mistrustful of the caucus format since the Iowa vote and are worried that further trouble could throw the Democrats' 2020 primary process into complete disarray. In Nevada, those fears have only deepened since the state's Democratic Party was forced to make abrupt changes to its caucus process because it had planned to use an iPad app developed by the same company that developed the mobile application used in Iowa.

Unlike primaries, which are run by state governments, caucuses are run by state political parties, raising questions about transparency. Additionally, voters must set aside several hours at a specific time to participate, which can limit access.

This has some top party leaders calling for an end to the format altogether. At the National Governors Association meeting Saturday, Kansas Gov. Laura Kelly, a Democrat, said caucuses are fundamentally flawed. "Kansas anticipated all of this, and we have abandoned the caucus process," Kelly said. "Part of the reason that we did that is because we understood the caucus process is really exclusionary, and really limits access to the process, for people with disabilities, for people who work evenings, for people who don't have transportation."

Top Nevada Democratic Party officials have tried to assure nervous Democratic voters that their fears are overblown. "Our main objective is running the most expansive, transparent and accessible caucus that ensures Nevadans' voices are heard," said Molly Forgey, a spokeswoman for the Nevada State Democratic Party.

But despite that show of confidence, multiple Democrats said that the influential former Senate majority leader Harry Reid of Nevada has been working to soothe candidate concerns about potential caucus drama. Many of his former aides are working for different campaigns nationally and here in Nevada.

"In Nevada, we have built the best state party operation in the country," Reid said in a Twitter message posted Tuesday. "I am 100% confident that what happened in Iowa will not happen in Nevada."

The reassuring words have done little to convince local officials that the party will be able to carry out its voting plan without problems.

Conducting caucuses is a particular challenge in Nevada, where there are more than 2,000 caucus sites across the state, including in some rural areas. Adding to the challenge this year is an ambitious early-voting plan designed to increase flexibility and participation. Nevada Democrats expect about 90,000 people to caucus; they expect more than half of this year's caucus-goers to vote early.

During early voting, Democrats are allowed to vote at any site in the state between Feb. 15 and 18, no matter their registered precinct. Under the original plan, upon arrival, voters would have ranked their top three presidential choices on an iPad-based app.

The plan was for that data to be transmitted to voters' home precincts for the Feb. 22 in-person caucuses. The local caucus leaders, using a second reporting app, were to have incorporated the early voters' choices into the first alignment and reallocate them if their first choices were not viable. The second app, used by the caucus leader, would have then transmitted the final results to the state party.

Both apps were designed by Shadow, the political technology firm responsible for the vote-recording app implicated in reporting problems in Iowa. On Thursday night, Nevada Democrats announced that they would no longer use any apps.

They did not explain what would replace them. Forgey said the party was still considering "all other options." Late Saturday, the Nevada Independent reported that party officials were developing "a tool," not an app, that would be preloaded on iPads to capture data. Forgey did not respond to a request for comment, but the state party already had a backup plan in case of technology failure - a phone number caucus leaders can call to receive data from the early vote. They would do the caucus math manually before phoning in the final precinct results to the state party.

Multiple campaign officials have since complained about a lack of transparency by the party. Though there had been multiple conference calls beginning Tuesday between the state party and the campaigns, several Democrats said party officials had been "tight-lipped" and slow to offer specific information about how the early voting would work.

"This is about Nevada and what happens one or two weeks from now," said one Democrat close to the process, who spoke on the condition of anonymity to avoid inflaming relations with state party officials. "But it's also about the Democratic Party as a whole. More chaos is bad for the party and bad for voting. We cannot afford to mess this up."

A state party official, also speaking on the condition of anonymity to discuss internal matters, disputed the claims, insisting that the party has been inclusive of the campaigns as it has sought to figure out the process ahead. "The frustration is not that we are not talking to them," the official said. "They are just not happy with what we are saying."

Even primary states haven't been spared increased pressure to report the vote early and to get it right. In New Hampshire, Democrats sought to reassure the public that their primary on Tuesday will run more smoothly than Iowa's vote, even if some voters will be casting their ballots on voting machines so old they are no longer manufactured.

The primary is run by the state government rather than by a political party. And because it is a primary, the total ballots cast will be the only figure used to determine a winner, unlike the multiple numbers reported in Iowa that have led to two candidates - former South Bend, Ind., mayor Pete Buttigieg and Sen. Bernie Sanders, I-Vt. - declaring victory.

"We are very confident that the election is going to go well on Tuesday and that we will report accurate results at the end of the night," said David Scanlan, New Hampshire's deputy secretary of state.

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The Washington Post's Isaac Stanley-Becker and Tim Craig in Washington contributed to this report.