Sadiq Khan has called Extinction Rebellion activists "allies" after they staged a 10-day protest which caused disruption across London.
In a meeting with the activists today, the London Mayor said he and the group could "work together" in lobbying the government on climate change.
"We take our responsibility as the government for London very seriously," he said in the meeting.
"We are with you in relation to lobbying the government government in relation to powers and resources, and we see you as allies in relation to lobbying the government."
He added: "We can work together."
The group are set to meet with environment secretary Michael Gove tomorrow, as well as shadow chancellor John McDonnell.
Extinction Rebellion activists brought London to a standstill during their protests, which included vandalising buildings and gluing themselves to public transport.
Over 1,000 protesters were arrested during the 10 days of demonstrations.