Campaign groups criticised Danish police for using heavy-handed tactics after nearly 1,000 people were arrested in Copenhagen during climate change protests.
Tensions rose and there were clashes with police during the increasingly angry protest to demand a fair and binding new global deal to tackle climate change.
It marked the halfway point of crunch United Nations climate talks in the Danish capital. But protesters said officers used an unnecessarily heavy-handed approach in dealing with the protesters.
The World Development Movement's director Deborah Doane said: "It's absolutely outrageous that the police responded in this extreme manner on an incredibly family-friendly march.
"It's a complete violation of the right to protest and a step towards the breakdown of democracy. This is the most crucial issue of our time and the people must be heard, not criminalised."
Campaign group Climate Justice Action claimed protesters had been indiscriminately arrested by Danish police.
Helga Matthiassen, who was campaigning with the group said she was detained for an hour before being released due to an injury she had recently sustained: "Not only have we been denied the right to protest, but our basic human rights have also been ignored in this ludicrous, staged police exercise."