Protesters heckle and throw tomatoes at Donald Trump during rally

Donald Trump has been attacked by protesters at a campaign rally in Iowa, with one yelling out “Heil Trumpler” and another throwing tomatoes at him.

The crowd of 1,900 were already agitated when Trump appeared on stage, after he arrived an hour late at the University of Iowa Field House.

Protesters repeatedly interrupted the presidential candidate’s speech as he spoke about Bernie Sanders.

Mr Trump reportedly called Mr Sanders “a communist” and that’s when 28-year-old Andrew Joseph Alemao launched two tomatoes at the stage – according to Daily Iowan reporter Brent Griffiths.

Mr Alemao was arrested by Secret Service and charged with disorderly conduct.

Mr Griffiths reported Trump’s "appearance came to an abrupt end (Trump has been known to speak for over an hour) after another round of protesters sounded off on their whistles.”

Immediately after his arrest, a GoFundMe page was set up for the arrested man to pay his legal expenses with 81 people donating over $1,500 but the page has now been taken down.