A zoo in the German city of Nuremberg says it has killed 12 baboons despite protests, capping a saga rooted in concerns that the zoo had too little space to house a growing group of the animals.

Police arrested 7 animal rights activists who briefly entered the zoo complex in the southern city of Nuremberg on Tuesday.

Nuremberg Zoo has sparked condemnation from animal rights activists after culling 12 baboons amid fears the group had grown too large for their enclosure.