A PROTESTER who slapped a police horse in the face at a Donald Trump rally has been charged with abuse of a police service animal.

Police had been searching for the woman who hit the horse at a Trump rally in Kansas City on March 12, The Kansas Daily Star reports.

April J. Foster, 29, was arrested on Friday following a tip-off from the public, who recognised her from a picture of the incident taken by a photographer for the paper.

This is April Foster...she was arrested yesterday for punching a police horse during last weekend's Trump rally. pic.twitter.com/lBfz4st6Pj — Megan Brilley (@fox4meg) March 19, 2016

The horse, named Dan, was hit while officers attempted to control protesters outside a Trump rally in downtown Kansas City.

According to the police report, Foster had first screamed in the horse’s face to scare him, and when that did not work, she hit the horse with her open hand.

After slapping the horse, she ran back into the gathering of around 200 protesters, and police were unable to find her due to the size of the crowd.

Foster, who lists “animal welfare” under “causes April cares about” on her LinkedIn profile, was released on a $US500 bond and will appear in court on May 4.

It comes after Arizona police officer Brandon Tatum described protesters at a Trump rally in Tucson as “the most hateful, evil people I’ve ever seen”.

In a video, which went viral on Facebook, the officer explained how he had attended the rally to find out more about Donald Trump’s policies for himself.

He said he was shocked by the behaviour of the protesters and feared he would “have to punch a couple of people in self-defence”. “These people were acting so outrageous,” he said.

“I could not believe what I saw. You were just thinking that somebody was going to lose their temper and there was going to be a full brawl.”

The Arizona rally made headlines after one protester was punched in the face by a black Trump supporter, but Officer Tatum said the protester had instigated the fight by spitting on or verbally assaulting an attendee.

According to a YouGov poll, the 68 per cent of Americans blame the “mainstream media” for the recent violence at Trump campaign events. Trump has condemned the protesters, who he describes as “professional agitators”.