Hillary Clinton
Former U.S. President Bill Clinton (rear) applauds his wife, Democratic U.S. presidential candidate Hillary Clinton, as they appear with their daughter Chelsea (R) at Mrs. Clinton's caucus night rally in Des Moines, Iowa February 1, 2016. Clinton won the Democratic race, narrowly defeating Bernie Sanders.Reuters

Hillary Clinton won the Democratic race in the Iowa caucus with the narrowest of margins over rival Bernie Sanders in the toughest fight the party has seen in the state. Clinton also became the first woman to win the Iowa caucus. 

Earlier on Monday night, Ted Cruz had emerged the Republican winner in the caucuses, defeating controversial businessman Donald Trump. 

Clinton and Sanders were neck and neck till the end of the results from Iowa's precincts, in what the Iowa Democratic Party called the closest-ever Democratic caucus in the region. 

"The results tonight are the closest in Iowa Democratic caucus history. Hillary Clinton has been awarded 699.57 state delegate equivalents, Bernie Sanders has been awarded 695.49 state delegate equivalents," Iowa Democratic Party Chair Andy McGuire said in a statement

Clinton's campaign claimed victory even as one precinct was to be reported. 

"After thorough reporting — and analysis — of results, there is no uncertainty and Secretary Clinton has clearly won the most national and state delegates. There is no outstanding information that could change the results," Hillary Clinton's campaign was quoted by USA Today saying in a statement. 

The Democratic Iowa caucus was reportedly too close to call even after 99% of the precincts had been reported.

The third Democratic candidate Martin O'Malley suspended his campaign Monday after seeing a poor show in the Iowa caucus.