Nineteen war graves have been damaged at Belfast City Cemetery.
Images released by police show gravestones at the site in the west of the city broken in pieces and lying on the grass.
The damage occurred some time between 7pm on Monday August 10 and 1pm yesterday, PSNI inspector Andrew McConville said.
He added: "Damage to any grave is absolutely despicable. A graveyard is a place where people come to pay their respects.
"This behaviour and the destruction of graves will have a significant impact on individuals, families and communities."
Detectives appealed for anyone with information to contact them.
