Hillary Clinton beats Bernie Sanders, Ted Cruz beats Donald Trump in Iowa.
• H. Clinton - 49.9%
• B. Sanders - 49.5%
• T. Cruz - 27.7% (winner)
• D. Trump - 24.3%
• M. Rubio - 23.1%
11PM: Clinton has claimed victory, CNN reports.
7.30pm: Hillary Clinton's campaign team is casting her performance in the Iowa caucuses as a win, even though she is separated from rival Bernie Sanders by just a few hundred votes.
Clinton spokesman Brian Fallon tells reporters that, "we believe strongly that we won tonight."
He's pointing to Clinton's capture of at least 22 delegates to the party's national convention to Sanders' 21, with one left to be decided.
Clinton spokeswoman Jennifer Palmieri says: "We feel like we have great momentum going into New Hampshire. This was a very hard fought state."
5.50pm: Bernie Sanders takes the stage and gives the most rousing speech of the evening. "It looks like we are in a virtual tie."
Sanders address continues the theme of the night, focusing on grassroots campaigning.
He said, "we can no longer continue to have a corrupt campaign finance system."
"The American people are saying no to a rigged economy. Are you guys ready for a radical idea? So is America."
"Iowa has begun a political revolution," he said.
He announced he will impose a tax on wall street to share wealth to those in need.
5.43pm: Nobody is ready to declare a projected winner for the democrat nomination. Sanders and Clinton are completely locked in a dead heat with 94% of votes counted.
5.30pm: Hillary Clinton is speaking to supporters despite the lack of result. Says "we can finish the job of universal health care," and combat climate change.
"I know we can protect women's rights, gay rights and stand up to the gun lobby."
5.20pm Clinton is very slightly up on Sanders; Cruz takes the stage and calls win "a victory for the grassroots" in an evangelical speech about God and America.
5.06pm: Cruz comes off bus tells media the result is "breathtaking."
5.03pm: Clinton and Sanders are virtually tied with only marginal numbers between them.
4.50pm: Trump takes the stage. "I love you people," he started
Trump remained humble and thanked Iowa for their support after getting second place.
"I absolutely love the people of Iowa. People told me not to come to Iowa, but I'm honoured to have come. We're so happy with the way things worked out."
"I might come here and buy a farm. I love it," he finished.
Someone managed to briefly change his name on Wikipedia to Donald "Trumped" following the news.
4.40pm: Marco Rubio is addressing his supports, brings up Hillary Clinton email scandal saying she's "disqualified from being next president."
4.36pm: Did Trump hurt his campaign by not attending the last debate? With votes still being counted, Marco Rubio could knock Trump out of the second spot which would be a massive blow to Trump.
4.31pm: Mick Huckabee suspends campaign.
I am officially suspending my campaign. Thank you for all your loyal support. #ImWithHucK— Gov. Mike Huckabee (@GovMikeHuckabee) February 2, 2016
4.25pm Fox, ABC, and CNN have declared Ted Cruz the winner of the Iowa caucuses for the Republican nomination.
4.11pm: Clinton and Sanders are nearing even - only 1% difference between them now!
3.50pm: Rubio is climbing now with 21.6%. Trump is at 25.1% and Cruz at 28.6%.
Sanders and Clinton are deadlocked with Clinton at 50.7% and Sanders at 48.6%.
The arcane democratic style of voting is causing confusion and exhaustion - recounts are being made at some caucuses meaning people need to stay on for extra hours. Sanders implored his voters to stay out as long as possible.
3.35pm: With 61% of the votes in for the Democrat election, Sanders and Clinton are too close to call. Bernie Sanders' surprise result is being touted as coming through his engagement with youth.
3:22pm: It's heating up in Iowa! Cruz and Trump at 29% and 27% respectively. Rubio is holding on at 19% with only the early results in.
Clinton and Sanders at 51% and 48%. It's an extremely close race for both parties.
3.11pm: We now have 16% of the vote results in. The gap is closing on Clinton and Sanders with Clinton down to 52% and Sanders up to 48%. Cruz has advanced slightly to take 30% with Trump down to 27%.
2.55pm: Vote counting is about to begin at some caucuses.
2.48pm: The latest numbers from CNN have Cruz and Trump neck and neck with Cruz at 31% and Trump at 30%. Rubio is sloping down on 16%.
Clinton and Sanders are still too close to call with 53% and 46% respectively. O'Malley has dropped even lower to 1%.
People are still lining up to caucus with record turnouts in Iowa.
2.34pm: CNN's early entrance poll gave Trump a solid lead at 27% with Ted Cruz next at 22% and Rubio at 21%. Dr. Carson is in last place with 9%.
The Democrat race is a little more binary with Clinton taking 50% and Sanders at 44% with Martin O'Malley sitting on a pithy 3%.
2.29pm: Trump delivers a short address to caucus goers insisting that Mexico is going to pay for a wall to strengthen United States borders.
2.11pm: Trump has turned up at a caucus site where he is shaking hands and taking selfies with supporters. Long lines at some caucus sites are delaying voting.
2.03pm: First ABC entrance poll puts Trump and Clinton in slight lead. Rubio and Cruz are tied for second.
2.00pm: Doors are closed and voting has begun.
1.54pm: With minutes to go, overflowing has started at some of the caucus sites around Iowa.
1.31pm: It looks like it's going to be a close contest between Bernie Sanders and Hillary Clinton. The voting registration is unusually high in Iowa this year.
The Republican nomination is between Ted Cruz and Donald Trump with Trump said to have a slight edge.
The high turn-out of new voters will tilt toward outsiders Trump and Sanders - both representing a political dynamic which would encourage otherwise non-voting persons.
- additional reporting AP