Firefighters were called into action after flames took hold of a church youth centre.
Seven crews tackled the blaze after it ripped through the first floor and roof of the building, part of the St Mark's complex in Kirkby.
Neighbours were urged to keep their windows and doors closed as crews battled the third fire at the site in three years.
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Emergency services were called to Brook Hey Drive at around 5.30pm on Sunday.
Fire crews arrived to find the first floor and roof space of the two storey youth centre at the church "well alight".
Merseyside Fire and Rescue Service said the fire spread over an area that measured approximately 20 metres by 40 metres.
Firefighters could be seen tackling the blaze from an aerial platform, while Merseyside Police cordoned off a section of Brook Hey Drive to traffic.
In an update issued while work was ongoing, Merseyside Fire and Rescue explained: "The incident has been divided into sectors, with main jets and high pressure hose reels involved in fighting the fire.
"The aerial appliance is also being set up to tackle the fire from height - all firefighting is being carried out externally at this point.
"Water supplies have been secured and a multi-agency meeting has taken place. Merseyside Police are in attendance.
"Local residents should stay inside and close windows and doors. If you have a pre-existing medical condition, keep medicines and treatment close and if any ill effects are experienced dial NHS 111 for advice."
The flames were quickly tackled but the wider operation continued well into Sunday night.
The church had previously suffered extensive damage in a fire back in 2018, while a blaze at another property on the site broke out as recently as May.
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