At least five people have died at a nursing home in Italy from suspected carbon monoxide poisoning, Reuters reports.

The incident happened at the Villa dei Diamanti care home in Lanuvio, a town near Rome, Italian firefighters said on Twitter. “Some residents have [been] killed, while others have been hospitalized,” it said.

Seven people, including two health workers, are treated in hospitals for symptoms related to carbon monoxide poisoning, the ANSA news agency said.