File photo: CGTN

US President Donald Trump on Tuesday described the Iowa caucuses an "unmitigated disaster" after officials were unable to declare a winner.

"Nothing works, just like they ran the country," Trump said in a tweet.

Iowa Democratic party officials blamed reporting problems for the delay in announcing a winner in the vote Monday night that kicked off the American election season.

Alluding to the fact that he won the Republican caucuses in the Midwestern farm state, Trump said "the only person that can claim a very big victory in Iowa last night is 'Trump.'"