Republican presidential candidate Carly Fiorina was surrounded by young children on Wednesday when she addressed the Iowa Right to Life presidential forum at the Greater Des Moines botanical garden -- and not all of the children's parents were happy about that.

One parent told the Guardian newspaper that the parents of those children had not given the Fiorina campaign permission to have the kids sit with her -- in front of a giant picture of a fetus. The children were simply on a field trip to the botanical garden at the same time as the forum and were "there to see the plants," said Chris Beck, the father of four-year-old Chatham.

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"She ambushed my son's field trip," Beck said.

The campaign responded that there was no "ambush."

In a statement, the campaign said the group of preschoolers, along with their parents and teachers, "followed Carly right into the event."

"Earlier, she'd run into the kids in the Botanical Gardens and watched the Koi with them for a while," the statement said. "The kids must have thought she was pretty neat because then their teachers and parents and the kids all followed Carly into the event, complete with Carly stickers."

Fiorina on Wednesday posted a short video of her impromptu meeting with the children:

Some special guests took a break from the snow to join me on a walk through the Greater Des Moines Botanical Garden. https://t.co/KTMiQXZ3fx — Carly Fiorina (@CarlyFiorina) January 20, 2016

Fiorina's deputy campaign manager, Sarah Isgur Flores, told CBS that the candidate honestly didn't realize that the kids were there for a field trip, and not there for the forum. She stressed that there were chaperones with the children who were wearing Carly Fiorina stickers.

"I can understand why those parents might be upset at the other parents who were there, but those parents and teachers wore Carly stickers and took the kids in," she said. Flores added that the kids were only there for about 10 minutes before they left.

At the event, Fiorina reiterated her intention to defund Planned Parenthood and endorsed the Pain-Capable Unborn Child Protection Act, the Des Moines Register reports.

CBS News' Sean Gallitz contributed to this report.