A 92-year-old US woman is accused of shooting and killing her son, 72, in order to avoid being sent into a care home, the BBC reports.

Anna Mae Blessing contemplated her son's intentions to put her into care for days, according to court documents.

"You took my life, so I'm taking yours," she reportedly said as she was escorted out of the Arizona home she shared with her son and his girlfriend, the BBC reports.

Blessing told police she had intended to kill herself, too.

The incident happened on 2 July in Arizona, police records show.

Blessing's son wanted her to leave for an assisted living facility because she "had become difficult to live with".

The mother hid two firearms in her robe pockets before facing him in his bedroom, police said in a statement.

During the ensuing argument, she pulled out one revolver, purchased in the 1970s, and fired at her son. The man was found dead with two bullet wounds to his neck and jaw.

Blessing then pointed the gun at her son's 57-year-old girlfriend, who managed to wrestle it away and throw it into a corner of the room.

She pulled out a second pistol, which she told police her late husband had given to her in the 1970s, the BBC report said.

The girlfriend managed to knock this one out of Blessing's hands, too, before escaping and calling the sheriff's office.

Police found Blessing in a reclining chair in her bedroom. She later told them she deserved to be "put to sleep" for her actions.

She is charged with first-degree murder, aggravated assault and kidnapping, and her bail was set at $500,000.