Extinction Rebellion protests have “stretched” police resources in London, the Metropolitan Police chief has said.
Dame Cressida Dick said she hoped the demonstrators would “protest lawfully” or “go home” after their “failure to take and occupy” certain streets.
More than 1,100 people have been arrested during a week of climate protests, including at Trafalgar Square and the BBC’s New Broadcasting House.
The campaign group has urged protesters not to co-operate if arrested.
Police have asked activists who have been demonstrating close to the Houses of Parliament in Westminster to move their protests in Trafalgar Square or risk arrest.
They served a Section 14 notice – designed to prevent “serious disruption” to communities – before removing those who had camped out in Westminster.
Dame Cressida said that if demonstrators protested lawfully she could deploy “many” officers “back to the streets, back to the neighbourhoods, back to the schools, back to the wards of the people of London”.
“We are responding to all serious matters and urgent matters of course, carrying on with our crime investigations in homicide or armed robbery,” she said.
“But we’re having to move work from one unit to another and the less urgent, less critical, less important work of course gets delayed.”
Extinction Rebellion has accused governments across the world of being “complicit” in the “climate and ecological emergency”.
“This peaceful non-violent disruption to your lives is nothing compare to the disruption that the inaction of our governments on the climate and ecological emergency will bring,” read a tweet from the movement’s official account.
In other tweets, it asked for people who are “willing to risk prison” to join, and called on protesters to “pledge to noncooperation” at police stations.
Extinction Rebellion activists are protesting in cities around the world, including Berlin, Paris, Amsterdam and Sydney, and are calling for urgent action on global climate and wildlife emergencies.
As part of their protests on Friday, activists gathered outside tents at Trafalgar Square and blocked the entrance to the BBC’s central London headquarters.
On Thursday, a Paralympic medallist climbed on top of a British Airways plane at London City Airport.
Another man refused to sit in his seat, delaying a flight by nearly two hours.
About 50 arrests were made at the airport.
Extinction Rebellion has yet to comment on Dame Cressida’s comments.