The Democratic Party's bid to choose a candidate to take on Donald Trump at the Nov.3 U.S. presidential election was in disarray on Tuesday, after technical problems delayed vote counting in Iowa to the dismay of the party faithful and the delight of the Republican president.

There was still no winner on Tuesday morning from Monday's Iowa caucuses voting, with officials blaming "inconsistencies" related to a new mobile app used for vote counting in the state that traditionally kicks off a U.S. presidential election year.

It was a clumsy start to 2020 voting, after a bad-tempered presidential campaign four years ago that produced a surprise winner in Trump and led to a two-year federal investigation into election interference by Russia.

The head of Iowa's Democratic Party promised to release results "as soon as possible" on Tuesday but said the top priority was ensuring the integrity of the process and accuracy of the results.

Democratic candidates left Iowa for New Hampshire, which hosts the next nominating contest on Feb.

11, without knowing who leads the race to take on Trump.