Climate campaigner Greta Thunberg was detained alongside a group of activists on Tuesday during protests against the demolition of the coal village of Luetzerath, according to police.

A spokesperson for the police division in the region said it was not yet clear what would happen to Thunberg, who joined protesters at the site last week to campaign against the expansion of the mine, owned by energy giant RWE.

Riot police backed by bulldozers removed activists from buildings in the village with only a few left in trees and an underground tunnel by last weekend, but protesters including Thunberg remained at the site staging a sit-in into Tuesday.

Thunberg was detained while protesting at the opencast coal mine of Garzweiler 2, some 9 kilometres (5.6 miles) from Luetzerath, where she sat with a group of protesters near the edge of the mine.

It was not yet clear what would happen to Thunberg or the group she was detained with, or whether the activist who jumped into the mine was injured, the spokesperson said, adding the police would provide an update within the hour.

Thunberg was carried away by three policemen and held by one arm at a spot further away from the edge of the mine where she was previously sat with the group.

She was then escorted back towards police vans.

The Swedish climate activist addressed the around 6,000 protesters who marched towards Lutzerath on Saturday, calling the expansion of the mine a “betrayal of present and future generations.”

“Germany is one of the biggest polluters in the world and needs to be held accountable,” she said.