The FBI have released images of a masked person in the hunt for news anchor Savannah Guthrie's mother.


Officials are seeking to identify the individual, who they say was armed, more than eight days after 84-year-old Nancy Guthrie disappeared from her home.


Savannah Guthrie said on Monday that her family believes their mother is still alive and issued a new appeal to anyone with information.


Nancy Guthrie disappeared in the middle of the night from her Tucson, Arizona, home and was last seen on January 31. Authorities believe she was taken against her will.


As of this morning, law enforcement has uncovered these previously inaccessible new images showing an armed individual appearing to have tampered with the camera at Nancy Guthrie's front door the morning of her disappearance, FBI Director Kash Patel said in a statement.


He said authorities had been working to recover images from the home surveillance system that may have been lost, corrupted, or inaccessible due to a variety of factors - including the removal of recording devices.


This marks the first major breakthrough in a case that has gripped the country for more than a week.


On Monday, police were still saying they had yet to identify any suspects or vehicles connected to Nancy Guthrie's disappearance, the same day Savannah Guthrie issued a new video appeal to anyone with information.


We believe our mum is still out there, she said in a video posted to her Instagram account. We need your help. The FBI is offering a $50,000 reward for any information.