Adele has doused the flames of billionaire business mogul Donald Trump’s presidential campaign, protesting to his unauthorised use of her songs.

The objection came as the US state of Iowa went to the polls, revealing it may be an uphill battle for Mr Trump to win the Republican nomination. And now he must do it without the uplifting soundtrack provided by one of the globe’s biggest popstars.

It made an already bad day even worse for the flamboyant former reality TV star. Although the frontrunner going into Iowa, Mr Trump lost by 4 per cent to rival Ted Cruz, while Hillary Clinton toppled Bernie Sanders by less than 0.5 per cent in the Democrat vote.

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Throughout his campaign, Mr Trump has used Adele songs to build the crowd atmosphere, most recently the “we could have it all” melody in 2011 hit Rolling in the Deep.

Fans questioned whether the singer was aware of it.

I wonder if @Adele knows that Donald Trump is using her music to promote racism and bigotry.

— Kevin Plantz (@KevinPlantz) January 20, 2016

It turns out she wasn’t.

“Adele has not given permission for her music to be used for any political campaigning,” a spokesperson for Adele told The Independent.

She was not the first musician to object to the unwanted attention.

Lawyers for Aerosmith’s Steven Tyler sent The Donald cease and desist letters after he featured their power ballad Dream On, while R.E.M. also said they did not “authorise or condone” the use of their songs.

“The media and the American voter should focus on the bigger picture, and not allow grandstanding politicians to distract us from the pressing issues of the day and of the current Presidential campaign,” they said in a statement to Facebook.

Clinton narrowly claims Iowa

Adele has put a stop to Donald Trump ‘Rolling in the Deep’. Photo: Getty

Mrs Clinton claimed a razor-thin victory over Mr Sanders, following a blistering win by Mr Cruz over the outspoken Mr Trump.

Mrs Clinton pipped Mr Sanders by just 0.4 per cent of the vote. The result was declared by her Iowa state director Matt Paul in the early hours of Tuesday morning (local time).

“It is rare that we have the opportunity we do now, to have a real contest of ideas – to really think hard about what the Democratic Party stands for and what we want the future of our country to look like,” Mrs Clinton told supporters earlier in the night.

She prevailed by only four delegates, according to party figures, and Mr Sanders, a self-described democratic socialist, declared the result a “virtual tie”.

“Nine months ago, we came to this beautiful state, we had no political organisation, we had no money, we had no name recognition, and we were taking on the most powerful political organisation in the United States of America,” he said earlier in the night.

Mr Cruz, a conservative from Texas, won with 28 per cent of the vote compared with 24 per cent for Mr Trump in the Republican contest.

Marco Rubio, a US senator from Florida, came in third with 23 per cent, easily making him the leader among establishment Republican candidates.

Republican presidential candidate Donald Trump said he was confident of victory ahead of the Iowa caucuses. Photo: EPA

The latest round of voting will conclude mid-year and each party will announce their nominated candidates in July, before the general election on November 8.

Former Maryland governor Martin O’Malley suspended his campaign after taking less than 1 per cent of the vote.

Mrs Clinton, 68, said she was breathing a “big sigh of relief” after the results. She lost to then-senator Barack Obama in 2008.

‘Blood in the water for Trump’

Mr Cruz’s win and Mr Rubio’s strong showing could dent the momentum for Mr Trump, whose candidacy has alarmed the Republican establishment and been marked by controversies such as his calls for a temporary ban on Muslims entering the United States.

“There is now blood in the water for Donald Trump,” Republican strategist Ron Bonjean said.

“Ted Cruz proved he could successfully beat back Trump attacks because he had a great ground game and identified well with evangelical voters.”

In a victory speech that lasted more than 30 minute, Mr Cruz thanked God and said the results showed that the nominee would not be chosen by the media, the Washington establishment or lobbyists.

Democratic presidential candidate Hillary Clinton addresses supporters as former US President Bill Clinton looks on. Photo: EPA

Mr Trump, 69, congratulated his victorious opponent and said he still expected to win the Republican nomination for the general election.

“I’m just honoured, I’m really honoured,” he told supporters.

The results could shift momentum in both races. Mrs Clinton hoped for a strong finish against Mr Sanders to vanquish his insurgent candidacy. Mr Sanders is leading in opinion polls in New Hampshire. Meanwhile, Mr Trump appears to be ahead in New Hampshire.

Former Arkansas Governor Mike Huckabee said he was suspending his campaign for the Republican party nomination.

Mr Huckabee won the Iowa caucus in 2008.

Iowa has held the first nominating contests, called caucuses, since the early 1970s, giving it extra weight in the US electoral process that can translate into momentum for winning candidates. The caucuses are voter gatherings that take place in 1100 schools, churches and other public locations across the Midwestern state.

The 2016 election is shaping up to be the year of angry voters as disgruntled Americans worry about issues such as immigration, terrorism, income inequality and health care, fuelling the campaigns of Mr Trump, Mr Sanders and Mr Cruz.

– with AAP