Hours after voting began there were no results as the state’s Democratic party said it was ‘simply a reporting issue’

The Democratic presidential primary contest has got off to a disastrous start after results from the highly anticipated Iowa Democratic caucuses were dramatically delayed due to “inconsistencies” in the reporting of the data.

The state’s Democratic party said it was performing “quality control” on the numbers “out of an abundance of caution”, after reports on Monday of problems with a phone app used to relay vote tallies.

After more than a year of campaigning, ideological clashes, policy debates and tens of millions of dollars spent, the Iowa results offer the first chance to see what support each of the Democratic presidential candidates actually has among voters.

But by 11pm local time, no results had been released. Caucus voting got under way across Iowa’s more than 1,600 precincts at 7pm local time, with voters declaring which Democratic presidential candidate they believe is best positioned to beat Donald Trump in November.

“We found inconsistencies in the reporting of three sets of results,” said Mandy McClure, the Iowa Democratic party’s communications director.

“This is simply a reporting issue. The app did not go down, and this is not a hack or an intrusion. The underlying data and paper trail is sound and will simply take time to further report the results.”

Facebook Twitter Pinterest Bernie Sanders greets supporters. Photograph: Craig Lassig/EPA

The state party said it would release the results on Tuesday but did not give a time. It had earlier said it was carrying out “quality control checks, making sure the numbers are accurate”.

Q&A What are the Iowa caucuses? Show Hide On 3 February, the midwestern state of Iowa will kick off the long process of choosing the Democratic party’s presidential nominee, who will take on Donald Trump in the US election in November. Most US states hold primary elections, in which voters go to a polling place, mail in their ballots or otherwise vote remotely. But a handful of states hold caucuses – complicated, hours-long meetings with multiple rounds of balloting until one candidate emerges as victor. Both Democratic and Republican caucuses will take place on 3 February. But because Trump doesn't face any serious Republican challengers, all eyes will be on the Democratic contest. Put simply, Iowans aged 18 (at the time of the November 3 election) and over who are registered Democrats will gather in caucus sites (school gyms, churches, community halls) in their designated precinct, and vote with their feet by splitting into groups based on their preferred candidate. Once voting is over at a caucus site, the support for viable candidates (those with more than 15% of the votes) is translated into a number of “state delegate equivalents”. That result is used to calculate the number of national delegates each candidate receives. National delegates eventually choose the nominee at the Democratic convention in July. On the night, the candidate with the most SDEs is considered the winner. Photograph: Jim Watson/AFP

Eleven Democratic candidates are competing to be the candidate to take on Donald Trump. Recent polls have showed four of the 11 remaining candidates knotted together at the top – the Vermont senator Bernie Sanders, the former vice-president Joe Biden, the Massachusetts senator Elizabeth Warren and the former South Bend, Indiana, mayor Pete Buttigieg.

Despite the lack of results, all candidates sought to claim a form of victory, before resuming their campaigns on Tuesday in New Hampshire, which will hold the next primary election next week.

Sanders, who appeared to have a narrow lead heading into Iowa, predicted he would do “very, very well” once results were finally released.

“I imagine, have a strong feeling, that at some point the results will be announced,” Sanders said. “The first state in the country in this has voted and today marks the beginning of the end for Donald Trump.”

Standing above a forest of camera phones amid chants of “We love Joe”, Biden told his supporters: “Folks, well it looks like it’s going to be a long night, but I’m feeling good.”

In a letter to the Iowa Democratic party obtained by the Guardian, lawyers for Biden’s campaign demanded “full explanations and relevant information regarding the methods of quality control you are employing, and an opportunity to respond, before any official results are released”.

Facebook Twitter Pinterest The former mayor of South Bend, Indiana, Pete Buttigieg (centre) and his husband Chasten Buttigieg at the ‘Pete for America’ caucus night. Photograph: Gary He/EPA

Warren told her supports that the results were too close to call and launched into a speech that sounded pre-written in anticipation of a strong performance. “Iowa, tonight, you showed that big dreams are still possible in America.”

Speaking to his supporters, Buttigieg said: “So we don’t know all the results. But we do know, by the time it’s all said and done, Iowa you have shocked the nation. Because by all indications, we are going on to New Hampshire victorious.”

The Buttigieg and Sanders campaigns released incomplete internal voting data that they said supported their claims of strong performances. The Biden camp responded by warning that no official data had been released, adding: “Our own model shows that Biden over performed in key districts … and we feel confident that this is a tight race with bunched up candidates.”

Joe Rospars, a top strategist on the Warren campaign, said: “Any campaign saying they won or putting out incomplete numbers is contributing to the chaos and misinformation.”

Meanwhile, the Trump campaign sought to paint Democrats as disorganised and chaotic, and suggested – without evidence – that the delays had raised doubts over the fairness of the voting process.

Play Video 3:13 How the Democrats will decide who fights Trump – video

“Democrats are stewing in a caucus mess of their own creation with the sloppiest train wreck in history,” said Brad Parscale, Trump 2020 campaign manager. “It would be natural for people to doubt the fairness of the process. And these are the people who want to run our entire healthcare system?”

Trump himself followed this up on Tuesday with a tweet calling the shambles an “unmitigated disaster”.

Republicans were also technically caucusing on Monday night, but with no serious competition for the nomination, Trump was quickly declared the winner.

Hundreds of thousands of Iowans – many of them still undecided when they walked into their precinct – had gathered on Monday evening in gymnasiums, libraries and churches to participate in the caucuses, the first official nominating contest of the 2020 primary.

But Democratic caucus officials reported struggling to report results using the phone app, and spending a long time waiting to deliver vote tallies via a backup phone hotline. In Howard county, which swung from Barack Obama to Trump in 2016, precinct officials said it was taking 20 minutes or more to get a call through to give results.

Facebook Twitter Pinterest Supporters of Bernie Sanders hold signs at a caucus in Des Moines. Photograph: Brian Snyder/Reuters

In the run-up to the caucuses, there had been a growing sense that Sanders had taken the lead while the other frontrunners were locked into a battle for second. A highly anticipated Des Moines Register/CNN/Mediacom poll that might have shed some clarity was canceled on Saturday night due to concerns with its methodology.

Rightwing groups spread false information about voter rolls hours before Iowa caucuses Read more

Biden has pitched himself as a steady pair of hands and the strongest choice against Trump, a view polling suggests is shared by a large constituency of Democrats, particularly among African Americans, who play a critical role in later contests. But he faces competition for moderate voters from Buttigieg, 38, who has risen from relative anonymity.

Facebook Twitter Pinterest Jo Biden is a popular choice among African American voters, polls show. Photograph: Jim Lo Scalzo/EPA

Warren, a former public school teacher and Harvard law professor, has pitched herself as an unabashed liberal with an arsenal of detailed policy proposals for “big structural change”. But in the last days of the Iowa race she has also sought to emphasize what her allies argue is her unique capacity to unite and excite Democrats from the party’s ideological factions, even as she confronts doubts that a woman can beat Trump.

Q&A Why are the Iowa caucuses important? Show Hide On 3 February, voters in the midwestern state of Iowa will kick off the long process that will eventually choose the Democratic party’s presidential nominee, who will take on Donald Trump in November's US election. The primaries and caucuses are a series of contests, in all 50 US states plus Washington DC and outlying territories, by which each party selects its presidential nominee. Iowa is extremely influential in US elections because, since 1972, it has voted first. After months of campaigning, this will be the first chance to see what support each of the presidential candidates actually have among voters. Winning Iowa matters because it can give candidates a huge boost in momentum and name recognition before the other states cast their votes. Underdogs can triumph, and frontrunners can fall. Since 2000, every Democratic winner of the Iowa caucuses has gone on to win the party’s nomination. However, Iowa only has a population of around three million people, who are 90% white, which has prompted criticism that its influence in US elections is outsized.

Tech entrepreneur Andrew Yang had predicted that he would “shock” the country.

The former New York mayor and billionaire Michael Bloomberg was not competing in Iowa, having spent more than $100m on a gamble that he would win big in later contests. Trump has fixated on Bloomberg and on Sunday their campaigns aired dueling TV ads during the Super Bowl.

Facebook Twitter Pinterest A volunteer holds a presidential preference card before the start of a Democratic caucus. Photograph: Charlie Neibergall/AP

The Senate impeachment trial added an additional layer of uncertainty to the already unusual Iowa caucuses, pulling Sanders, Warren and Amy Klobuchar – and the long-shot Senator Michael Bennet – back to Washington in the final weeks. Republicans are poised to acquit Trump on Wednesday, leaving the fate of the presidency in the hands of the Democrats running to defeat him.

“We better not screw this up,” Klobuchar, the senator from Minnesota who has staked her candidacy on a strong finish in Iowa, told supporters.

Additional reporting: Joan E Greve, David Smith and Adam Gabbatt in Des Moines and Chris McGreal in Cresco

