'Mum is still out there' - Savannah Guthrie issues new plea as ransom deadline passes

US news presenter Savannah Guthrie has said her family believes their abducted mother is still alive, as she issued a new 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."

As a reported ransom deadline for the safe return of Guthrie's mother Nancy passed on Monday, officials said they had still not identified a suspect or person of interest.

The 84-year-old disappeared in the middle of night from her home in Tucson, Arizona, and was last seen on 31 January. Authorities believe she was taken against her will.

The family had earlier indicated that they would be willing to pay for her safe return.

The FBI said they are not aware of "any continued communication between the Guthrie family and suspected kidnappers". It is offering a $50,000 (£36,000) reward for any information.

The FBI also said it is taking an email with a ransom note sent to US media outlets stating the Monday deadline seriously, the BBC's US partner CBS reported.

A previous alleged deadline for ransom, which was meant to be paid in Bitcoin, passed on 5 February.

Nancy wasreported missing when she did not attend a Sunday church service on 1 February and other members grew concerned.

The family has released three other videos saying they were willing to speak to the potential abductors, and asking for proof that their mother is still alive.

"I just want to share a few thoughts as we enter another week of this nightmare," Savannah Guthrie says in the latest clip, in which she appears alone unlike previous recordings where she has been joined by her siblings.

"She was taken, and we don't know where. And we need your help," Guthrie says.

Guthrie requests people everywhere, "even if you're far from Tucson", to report anything suspicious that could lead to clues about her mother.

She continues: "If you see anything, if you hear anything, if there's anything at all that seems strange to you, that you report to law enforcement".

In an update just before Monday's deadline, the Pima County Sheriff's Office said it did not have any new information to release publicly.

The sheriff's statement added that the "investigation into Nancy Guthrie's disappearance remains active and ongoing", and that "the FBI is handling all aspects related to any ransom note(s) or communications involving the Guthrie family".

The FBI also released a statement, saying that FBI agents from around the country "continue to deploy to Tucson".

"We are currently operating a 24-hour command post that includes crisis management experts, analytic support, and investigative teams. But we still need the public's help," the FBI statement added, including the number for the FBI's tip line.