Exxon Mobil UK, one of the country’s largest privately-owned underground oil pipeline distribution networks, confirmed demonstrations were under way at some of its sites on Friday morning.
Just Stop Oil said it blocked “10 critical oil terminals” across the UK.
Activists are sat on roads preventing tankers from leaving the sites.
The group claimed that more than 30 young people climbed on top of tankers at Navigator Oil Terminal, Thurrock.
Essex Police said they have made six arrests “so far”.
Just Stop Oil of their activists during their blockade of Esso Birmngham Fuel Terminal early on Friday
Just Stop Oil
West Midlands Police tweeted: “We are working to deal with this as quickly as possible.”
The force added that delays were expected on Wood Lane, Bromford Lane and Tyburn Road.
Extinction Rebellion supporters joined the protests.
Just Stop Oil of their activists during their blockade of Esso Birmngham Fuel Terminal early on Friday
Just Stop Oil
Just Stop Oil said in a statement: “The Just Stop Oil coalition is demanding an end to the Government’s genocidal policy of expanding UK oil and gas production and is calling on all those outraged at the prospect of climate collapse and suffering from the cost-of-living crisis to stand with us.
“Ordinary people can no longer afford oil and gas, it’s time to Just Stop Oil.
“It’s funding war and killing people in the global South, while destroying the future for young people everywhere.”
Exxon Mobil UK wrote on Twitter: “Small protests are currently underway outside our Hythe, Birmingham and West London fuel terminals.
“While we respect the right to peaceful protest, our priority is the safety of our people, our neighbours, the protestors and our operations.
“We are working with the police to ensure that safety is maintained.”
The firm said it had temporarily suspended operations at the locations mentioned, but its other terminals at Purfleet and Avonmouth were not affected.
Just Stop Oil supporters have disrupted Premier League football matches by running onto the pitch and tying themselves to goalposts in recent weeks.
The group listed seven locations they say protests have taken place:
– Inter Terminals UK, Grays, Essex
– Navigator Terminals Thames, Grays, Essex
– Buncefield oil depot, Hemel Hempstead, Hertfordshire
– Esso Birmingham Fuel Terminal, Birmingham, West Midlands
– Esso West London Terminal near Heathrow Airport, west London
– BP’s Hamble Oil Terminal, Southampton, Hampshire
– ExxonMobil’s Hythe Terminal, Southampton, Hampshire