A butcher has been forced to hang a window sign saying killing animals is “violent and unjust” to stop animal rights activists from staging gruesome protests in front of the shop.

Owners of the Local Butcher Shop in California agreed to hang the sign after protesters staged weekly rallies outside the Berkeley store front, lying nearly nude on the pavement, painted in fake blood and wrapped in plastic.

Protesters from Direct Action Everywhere told owners Monica and Aaron Rocchino they would stop the rallies if they hung a sign condemning the killing of animals, according to The Guardian.

But despite the owners' acceptance of the controversial offer, the activists retained the right to two protests a year and insisted the agreement was "temporary".

Ms Rocchino, who has owned the shop with her husband since 2011, criticised the agreement as a form of "blackmail".

"To be threatened and forced to abide by their beliefs just makes me sad," she said. "Their tactics are really extremist … This is ethical extortion."

Berkeley Mayor Jesse Arreguín said the activists’ pressure was "harassment - plain and simple."

The sign reads: 'Attention: animals' lives are their right. Killing them is violent and unjust, no matter how it's done.' (Facebook/Direct Action Everywhere)

"Demanding that the store hang a sign stating the group's views in exchange for an end to protests is coercive, improper and not the way to treat a much-loved local business. Our independent stores are the lifeline of our community and should not be harassed for simply doing their jobs," he wrote on Facebook.

"I support Monica and Aaron Rocchino, owners of The Local Butcher Shop, who are doing more than many other grocers to buy locally sourced animals raised in humane conditions. If you're against eating meat, don't eat it, but don't impose your beliefs on others either."

But Direct Action Everywhere said the move was a big victory for the group, who want to see Berkeley become a meat-free city by 2025.

"Following over a dozen investigations showing horrific cruelty even on so-called 'humane' farms, activists with Direct Action Everywhere (DxE) recently negotiated the posting of a sign at a 'humane' butcher shop which publicly criticises the inherent violence and injustice of killing animals," the group wrote.