Four elderly residents of the same nursing home died after showing symptoms of coronavirus, counsel said.
A fifth symptomless person also died at Harry Sotnick House in Portsmouth, Hampshire.
A number of other residents who may also have Covid-19 are being looked after in isolation in the home, said Portsmouth City Council.
Council chief Gerald Vernon-Jackson said the house was being used by the council to relieve pressure on the NHS.
Two of the deceased were recently admitted to the Hampshire County Council-run hospital, but Vernon-Jackson said he was unsure if they had been transferred to the Queen’s Hospital Relief Program Alexandra of Portsmouth.
Three of those who died were existing residents.
City council said there has been no test for Covid-19 of those who have died, as the stipulated guidelines should not be used if there will be no change in the care provided.
“It is incredibly sad for everyone, the families and the people who work there,” said Vernon-Jackson.
“I think it becomes clear as it happens in France, Spain and Italy, one of the areas most at risk is that of people living in nursing homes and retirement homes. “
He said personal protective equipment (PPE) was a “real problem” for the 39 nursing homes in the city.
“The things that were supposed to happen on the government weekend were not.
“When I spoke to people working in nursing homes, they were very worried because they were exhausted or exhausted. “
The council said it did not know how many people were currently being treated in the 92-bed house and that it was working with public health specialists in England (PHE) during the epidemic.
The house has been thoroughly cleaned and caregivers are still working under the direction of PHE, he added.
It has been closed to visitors since March 22.