Unclaimed urns containing ashes of the dead are piling up by the thousands across Japan, creating storage headaches and reflecting fraying family ties and economic pressures in a rapidly aging nation.

The identities of the dead, cremated at public expense, are usually known. But in most cases, relatives either refuse or don't respond to requests to collect their remains. Burials can be costly and time-consuming, a burden on family members who may hardly know the deceased relative.

"When I die, though I have only ¥150,000 ($1,340), will you cremate me and put me in a pauper's grave? I have no one to collect my remains," said a note left by a man in his 70s in Yokosuka who died in 2015 and whose urn was later buried at a local temple.