ALLENTOWN, Pennsylvania (AP) - An elderly man who shot and killed his 83-year-old wife in an eastern Pennsylvania hospice unit on Tuesday and then committed suicide, had apparently decided he could not live without her, authorities said.

Staff members heard gunshots on the fourth floor of Lehigh Valley Hospital in Allentown shortly after 1 pm local time. When they entered the room where the shots were fired, they found Mrs Mildred Osman dead in her bed, along with the body of 86-year-old Elwood Osman, said Lehigh County District Attorney Jim Martin.

The shooting "preliminarily appears to be a murder-suicide," Mr Martin said. The Lehigh County coroner's office said autopsies on both are scheduled for Wednesday.

Mr James Geiger, senior vice-president of the hospital, was asked at a news conference if Mr Osman's shooting death appeared to be a "mercy killing."

"It's a love story," Mr Geiger responded. "The elderly gentleman could not bear to see his wife suffering, and the family, I believe, have observed that he just could not envision living without her." He said he didn't know of any note left behind.

No other patients or staff members were harmed or threatened, and the hospital was not evacuated, officials said.

"This is a very tragic event and our hearts go out to the family of the deceased and our Lehigh Valley Health Network colleagues who were involved," said Mr Chuck Lewis, the hospital's senior vice president of external affairs.

No one witnessed the shooting, and the man gave hospital staff no indication that he was about to harm his wife, who had entered the hospice more than a week ago, said police Captain Glen Dorney.

"The first thing that drew their attention was the sound of the gunshot," he said. "They heard a second gunshot and came to investigate."

Like most hospitals, Lehigh Valley Hospital does not use metal detectors to screen visitors, though wands are used when hospital security has reason to believe a patient has a weapon, Mr Geiger said.