Voters in the rural state of Iowa are preparing for the first test of the US election season as they choose a Republican candidate to take on Barack Obama for the White House in November.Mitt Romney, Ron Paul and Rick Santorum lead a field of six contenders in a race that remains too close to call.
They are making last-ditch efforts to win over the many undecided voters.
Tuesday evening's caucuses will involve about 120,000 Iowans gathering in homes, schools and public buildings.
Spread across some 1,700 meetings in all of Iowa's 99 counties, Iowans will elect 28 delegates to the Republican National Convention, where the party's eventual nominee will be anointed in Florida this August.
Spreading the message Candidates spent Monday in a last-minute flurry of campaign events at coffee shops, pizza restaurants and hotel lobbies in an effort to to win over undecided voters.