West Yorkshire Police has said it is investigating reports received since a group of so-called 'tyre extinguishers' claimed to have deflated the tyres on 85 SUVs across Leeds overnight.
The Tyre Extinguishers group said they had taken "emergency action" to let down the tyres on vehicles in Meanwood and other areas.
They describe themselves as "ordinary people terrified by the complete unwillingness of governments, corporations and individuals to combat the climate and nature crisis".
They say they have carried out the act of deflating tyres in many cities across the world, including London, in recent months.
A police spokesperson said: “Police are carrying out enquiries today following reports of tyres on a number of vehicles being let down overnight in the Meanwood area of Leeds.
“No physical damage was caused to the tyres of the 4x4 type vehicles which were targeted.”
In a statement explaining their motivations, Tyre Extinguishers said SUVs - even electric ones - were “simply not compatible with a liveable future”.
The group says the tyres had been deflated using the valves, with "no irreversible damage".
No cars with blue badges or traders' vehicles were affected, according to the group’s statement.
Police are asking that anyone whose car was targeted but has not yet made a report does so.
Anyone who needs to make a report can visit www.westyorkshire.police.uk/101livechat or contact the Leeds North East Outer NPT via 101.
Information can also be given anonymously to the independent Crimestoppers charity by calling 0800 555 111 or visiting its website.