XR members flooded Oxford Street and surrounding roads near Oxford Circus on the third day of the climate action group’s campaign of disobedience.
Women with climate messages written on their bodies brought traffic to a standstill just before 2pm, and campaigners climbed on a pink sculpture they had erected in the road.
Police using loud speakers warned the XR protesters to leave or face being arrested.
But they formed a human chain around the area and some glued themselves to the pink structure.
Dozens of people were carried away to nearby police vans, with other members of the group cheering and clapping.
Pedestrians were urged to find another way around the area.
“We’re pleased to announce that Oxford Street and Oxford Circus have been pedestrianised,” the group tweeted.
“Meanwhile Westminster Council is placed in People’s Special Measures for not already having done this.”
At least 10,000 people have gathered at the protests across the capital. Scotland Yard said as of 6pm on Wednesday a further six had been arrested for a “variety of offences”.
It brings the total number of arrests made over the four days of protests to 196.
Earlier in the day a Fint (female, intersex, non-binary and trans) protest rallied at the statue of Eros in Piccadilly Circus and marched through Soho.
Wednesday also saw activists from Money Rebellion, an offshoot of Extinction Rebellion, gather at the Department for International Trade and hold a mock awards ceremony where a “Charred Earth” award was given to the department.
Money Rebellion said the “ironic award” was “presented to those who are making an outstandingly awful contribution to climate change”.
Other activists gathered at the Brazilian embassy to show solidarity with indigenous people in the Amazon Rainforest.
The Metropolitan Police said: “Officers have intervened when protestors were building a structure at OxfordCircus.
“Some individuals have glued themselves to the structure, specialist officers are working to support their removal.
“There will be some disruption to traffic in the area as roads are currently blocked, which we are working to reduce.”
The demonstrations continue next week, when the activists will protest against the links between “big finance, fossil fuels and the fossil of politics that is Westminster”.