Dutch police on Tuesday arrested around 20 climate change protesters from the Extinction Rebellion movement after they staged a demonstration at the International Criminal Court in The Hague, officials said.

The protest at the tribunal, which is more used to dealing with war crimes and genocide, came a day after the same grassroots environmental group blocked key roads in London.

“A number of persons entered the premises of the ICC today, as general visitors to the court. After that, they grouped and started demonstrating outside the ICC building,” ICC spokesman Fadi El Abdallah told AFP.

“They were evacuated by the Dutch police in a peaceful way.”

A picture tweeted by Extinction Rebellion’s Dutch branch showed the protesters unveiling banners inside the ICC’s premises on a bridge between the security gate and the main court building.

The group said that 25 “rebels” were involved and that they wanted to get the ICC’s 122 member countries “to recognize ecocide as an international crime.”

“We can confirm that around 20 demonstrators of this action group have been arrested in the ICC today. They had invaded the building and were arrested on the basis of trespass,” a Dutch police spokesman said.

The “Extinction Rebellion” group was established last year in Britain by academics to attract attention to the slow response of governments around the world to rising temperatures and sea levels caused by greenhouse gas emissions.

On Monday over a thousand protesters blocked central London’s Waterloo bridge and choked off key streets. More than 100 were arrested.