Church-goers were left in tears after thieves
stole more than 100 brass plaques erected in memory of loved ones, many
of them war dead.
Police say they were stolen between 19:00 BST last Thursday and 15:00 BST last Friday.
Father Cyril Thadathil said the congregation was devastated.
He said the thieves had taken all of the plaques at the memorial garden, many of which paid tribute to men who served in World War II.
He said when he made the discovery it was "so painful".
"It was the memory of so many people of our parish, people who have worked so hard for the church and people who sacrificed their life in the Second World War," he said. "As soon as I saw it I was upset."
He said that when he told worshippers what had happened "there was a great silence in church and many of them actually cried".
He also appealed to the thieves to return the plaques.
"If possible please do return them to the church because it's not about money because it's the memories and dignity of human life," he added.
Ronald Morgan, 75, of Gendros, Swansea, said the timing of the thefts made it even more poignant, with remembrance services taking place in November.
"There were a lot of people whose names are ex-military personnel and their husbands and grandfather who were in memory," he added.
South Wales Police said they are investigating the theft and appealed for witnesses or anyone who has information to contact 101 or Crimestoppers on 0800 555 111.