Animal rights activists briefly interrupted Pope Francis' weekly audience at the Vatican on Wednesday, holding up signs demanding an end to bullfighting.
Two activists from PETA, an international charity which defends animal rights, shouted slogans just as the audience got underway, before being escorted out.
The pair were briefly detained by Vatican security and Italian police, before being released, PETA said.
"Bullfighting is a sin", read the signs in English and Italian, while the activists' T-shirts read "Stop blessing corridas".
"Corridas", or bullfights, are a controversial tradition practised in Spain and several Latin American countries as well as in parts of southern France and Portugal.
Each year, thousands of bulls are slaughtered in bullrings around the world, according to PETA.
Wednesday's protest was one of several over the past couple of years calling for a stand against bullfighting from the Argentinian pope. In a 2015 treatise, he wrote that "every act of cruelty towards any creature is 'contrary to human dignity'".
In the 16th century, Pope Pius V banned bullfights as "cruel" and contrary to "Christian piety and charity".
But Catholic priests still officiate at religious ceremonies in bullfights and minister to bullfighters in chapels built inside arenas, PETA said.
While considered a venerated cultural tradition in Spain, bullfighting is a blood sport involving taunting and stabbing the bull before killing it.
Men on horseback first lance the bull in the neck, then others attempt to plant sharp sticks into its shoulders.
The matador then confronts the weakened, confused bull, engaging it in a series of passes with his cape before performing a fatal sword thrust between the shoulders to kill it.
It often takes multiple stabs to finally kill the animal.
Colombia's president last month enacted a law banning bullfighting, which will come into force from 2027.
Other Latin American countries that have outlawed bullfighting include Argentina, Brazil, Chile, Guatemala and Uruguay.
