US presidential candidates are making a final pitch to people in the state of Iowa, where the first votes for party nominations will take place on Monday.
Polls suggest that business tycoon Donald Trump has a lead over Ted Cruz and the other Republican candidates.
But the Democratic race is much tighter, with former US Secretary of State Hillary Clinton just edging ahead of Vermont Senator Bernie Sanders.
Each party’s nominee will contest the presidential election in November.
Over the weekend, the candidates barnstormed the sparsely populated Midwestern state of Iowa in a last-minute attempt to court undecided voters.
Candidates are hoping to triumph in this first electoral test because victory can spark campaign momentum as voting moves to the other states.
Amongst the wide Republican field, recent polling suggests that businessman Trump has a comfortable, though not certain, lead over his main rival, Texas Senator Cruz.
The Democrats’ far smaller field – three candidates as opposed to 11 – appears to be more competitive, reports the BBC.
Frontrunner Hillary Clinton has a commanding lead nationally but in Iowa she is narrowly ahead of self-proclaimed Democratic socialist Bernie Sanders.
One issue that could have implications in Iowa is the weather.
The National Weather Service is currently forecasting a winter storm to strike the area on Monday night.
