US elections 2016: Polls tight for Iowa caucuses
US presidential candidates are making their final pitches to people in Iowa, where the first votes for party nominations are taking place.
Polls suggest that Republican Donald Trump has a narrow lead over Ted Cruz, but both are well ahead of the others.
The Democratic race is slightly tighter, with former US Secretary of State Hillary Clinton edging ahead of Vermont Senator Bernie Sanders.
North America Editor Jon Sopel reports from Iowa.
01 Feb 2016