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 and 1pm on Tuesday, 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.
Sinn Fein MP Paul Maskey said the cemetery was a sanctuary for people.
“It is a place where families can go and pay respects to their loved ones and where they find peace and comfort.
“The desecration of any grave is totally unacceptable and is be condemned without reservation.
“There has been a great deal of work that has been done in the City Cemetery in recent times and there is work ongoing at the minute on the building at the Whiterock Road entrance.
“This investment will totally transform the cemetery and greatly enhance the site for families and tourists.
“I am encouraging people to report any suspicious activity as a matter of urgency to the council authorities, local elected representatives or the PSNI.”