An undisclosed number of residents remained unaccounted for Sunday, three days after a five-alarm fire began at a Pennsylvania continuing care retirement community, injuring 27, according to authorities.

The fire that began Thursday night at Barclay Friends in West Chester, PA, about 35 miles west of Philadelphia, is believed to have started in the assisted living memory care area, a spokeswoman for not-for-profit parent company Kendal Corp. told the media. It spread to multiple buildings, and video and photographs show extensive damage.

In addition to assisted living and memory care, the community also offers independent living, skilled nursing and post-acute rehabilitation.

A total of 132 residents and almost 30 staff members were at the community at the time of the fire, Kendal Chief Marketing Officer Colleen Ryan Mallon told McKnight’s Senior Living. Local fire departments said the fire was under control at approximately 1:30 a.m. on Friday, although it continued after that time. “Hot spots” were still evident on Saturday, officials said.

Kendal President and CEO Sean Kelly called the fire “tragic” and “a catastrophe” in a Friday post on the company’s and community’s websites.

“Despite a swift, effective, and compassionate response by first responders, along with Barclay Friends staff and so many volunteers, the physical loss is devastating and the emotional toll, even more so,” he wrote.

A Saturday posting on the community’s website said that more than 40 current and former staff members arrived on the scene “on their own volition” to help care for residents as they were being evacuated. “Additionally, there were dozens of staff at triage centers to help through the night,” the message said.

Some residents were evacuated to local hospitals and shelters, and others were picked up by family members. West Chester University President Christopher Fiorentino posted on the university’s Facebook page that 40 residents were evacuated to the school’s gym. The educational institution is part of a “collaborative emergency response network,” he said, and served as a triage location from which the residents then were sent to area facilities.

Kelly said Friday that residents are now located over many different area communities as more permanent transitions are planned. In a message posted Saturday, Barclay Friends said that the community was “distraught” that some residents remained unaccounted for. Sunday, Mallon could not provide details on the number of residents whose whereabouts are unknown.

The West Chester Borough Police Department said it is investigating the fire with local and state officials.

Residents’ families were invited to a local fire department on Sunday to pick up donated clothing and other supplies. Volunteers had collected slippers, shoes, pillows, blankets, towels, toiletries, walkers, reading glasses and additional items.

“Community members have turned out in droves, and donations have far exceeded expectations,” Barclay Friends said.

Donated items were expected to be available on Monday as well.