About six windows at a Chorley church were smashed by vandals over four consecutive evenings.
Offenders threw mud, cobbles and rocks at the plain-glass windows of All Saints Church on Moor Road.
The damaged windows are likely to cost hundreds of pounds to replace but Father Edmund Straszak will not be replacing the glass until a security fence is installed.
“Who knows the motives for people who do such acts,” he said.
“Over four consecutive evenings they threw cobbles, rubble or anything to hand.
“I’m not replacing the glass until the security fence is in place, there’s no point.”
Although vandals have targeted the church over the years it had been left unharmed over the last year or so.
Speculating over who might have destroyed the windows the Father added: “It was youths, I guess, congregating on the hidden side, the south side of the church.
“I don’t believe that these were premediated attacks, I can only guess it was fuelled by other things.
“Neighbours of the church tell me that they are often disturbed by gangs of youths who drink and take drugs.”
According to Lancashire Constabulary the vandals smashed the churches windows between Thursday, July 27 and Sunday, July 30.
On the first night three windows were broken between 5.30pm on Thursday and 8.15am on Friday.
A police spokesman said: “Someone approached the church and threw stones and mud at the windows, breaking three.”
For the following three nights on the trot vandals threw stones, pebbles and mud, breaking at least another three plain-glass church windows.