Police are investigating a new message sent to a local TV news station that might be linked to the suspected abduction of the mother of US news presenter Savannah Guthrie.

Authorities on Friday said they were "aware of a new message regarding Nancy Guthrie". They are "inspecting the information provided in the message for its accuracy".

The new development comes amid public pleas from the Guthrie family for proof that their mother is still alive and after the first deadline in one of the alleged ransom letters passed on Thursday evening.

The 84-year-old is believed to have been taken from her home in Tucson, Arizona, last weekend. Police are offering a reward of $50,000 (£36,000) for information.

The statement from the FBI and the Pima County Sheriff's Department did not specify who received the note, or any details that it may have contained.

A presenter for a local affiliate of CBS News told the BBC that her channel received the "message". It is unclear if it was sent to other media outlets.

On Thursday, Camron Guthrie - the son of the missing woman - renewed the family's plea, and confirmed that the family had not had any direct contact with kidnappers.

"We have to know that you have our mum," Camron said in the family's latest video message. "We want to talk to you."

"We haven't heard anything directly," he said in the video, posted on Thursday just after 17:00 local time in Arizona (00:00 GMT).

"We need you to reach out, and we need a way to communicate with you so we can move forward."

The case has mystified the country and even US President Donald Trump has weighed in, ordering federal authorities to help investigate.

On Friday, Trump said authorities had uncovered "some clues" and added that "we could have some answers" soon in the case.

The new message is one of several that authorities say they are investigating.

At a briefing on Thursday, FBI Special Agent Heith Janke said his agency was reviewing one of the notes, which he called a possible ransom note. It gave a deadline for payment of 17:00 on Thursday, he said, without specifying which time zone, and had a second deadline for Monday.

No further information was shared about what was threatened if the deadline was not met. "We're not going to go into specifics," Janke said.

It was announced the same day that authorities had made an arrest over a fake ransom note.

Earlier in the week, Savannah Guthrie shared an emotional video message, along with her siblings.

The host of NBC News' Today programme addressed the potential abductor or abductors directly, saying: "We are ready to talk... We need to know without a doubt that she is alive and you have her... Please, reach out to us".

Pima County Sheriff Chris Nanos said on Thursday investigators were no closer to finding out who was responsible - but that they were working on the assumption she was still alive.

"Right now, we believe Nancy is still out there. We want her home," he said. "Everybody's still a suspect in our eyes."

Dozens of reporters and camera crews have descended on the quiet Arizona suburb where Nancy lives.

Authorities have closed access to her street, nestled below the Santa Catalina mountains on roads lined with the state's iconic Saguaro cactus.

"Investigators are conducting follow-up at the Guthrie home and in the surrounding areas," police wrote in a post on X, adding that the road is "restricted to provide investigators space".

One man, when asked how he felt about security, shouted that he had already been interviewed four times today and wasn't doing any more. He then showed us a big stick, saying this is all the security he needs. He added he was not worried about kidnappers but he was worried about javelina, the hoofed mammals found in Tucson.

Authorities have urged the public to call the sheriff's office with any information, vowing to look into all leads, and discouraging the spread of misinformation. (BCC)