The mysterious disappearance of the 84-year-old mother of a star presenter on the American channel NBC News, probably abducted on Saturday night from her home, is causing a stir in the United States, even reaching the White House.

"We need to know beyond a shadow of a doubt that she is alive and that you have her," pleaded journalist Savannah Guthrie tearfully in a video posted on her social media Wednesday night to her mother's alleged kidnappers.

Nancy Guthrie was last seen at her home near Tucson on Saturday night.

Arizona police are focusing on the kidnapping theory. "She didn't leave of her own free will, we know that," said local Sheriff Chris Nanos at a press conference Monday, describing Nancy Guthrie's home as a "crime scene."

US President Donald Trump indicated on his Truth Social platform Wednesday that he had spoken to Savannah Guthrie.

"I am directing ALL federal law enforcement agencies to be, IMMEDIATELY, fully available to the family and local law enforcement," said Donald Trump.

"We are deploying all resources to ensure that her mother returns home safe and sound," he added.

In her video, Savannah Guthrie described her mother's fragile health. "She lives in constant pain. She's off all medication. She needs it to survive, and she needs it to not suffer," said the Today show host.

Usually radiant, the tearful journalist indicated that her family was striving to do "everything in our power" to find Nancy.

She also addressed her late mother directly. "Mom, if you can hear me, you are a strong woman. You are God's precious daughter, Nancy," she said.

According to the New York Times, Nancy Guthrie's disappearance was reported after she failed to show up for her usual Sunday church service.