San Juan, Puerto Rico (CNN) Down the street from La Fortaleza -- the mansion of Puerto Rico's embattled governor -- is the oldest cathedral on the island, San Juan Bautista Cathedral.

It's where many locals come to pray and find comfort amid the protests that have roiled the US territory since last week. But on Monday, the church won't offer refuge.

Its doors will be closed, as they were for most of the day Sunday for safety reasons, Father Benjamin Perez told CNN.

Last week, the church's doors were spray-painted with the words "resign dictator" and the building was damaged.

Now, with thousands expected to protest through the capital on Monday, Perez is afraid people may burn the building's doors.

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