American TV host Savannah Guthrie says her family is offering a $US1 million ($1.4million) reward for information leading to the return of her kidnapped mother Nancy Guthrie.
The 84-year-old was last seen on January 31 when she was dropped off at her home near Tucson, Arizona, by her family and was reported missing by relatives the following day, authorities have said.
On Tuesday, Savannah Guthrie posted a video message on Instagram pleading for information about her mother.
"Every hour and minute and second and every long night has been agony since then, of worrying about her, fearing for her and aching for her," Savannah Guthrie said.
"And most of all missing her."
Ms Guthrie asked people to continue their prayers for her mother.
"We still believe in a miracle," she said.
"We still believe that she can come home ...
"We are blowing on the embers of hope."
'Someone out there knows something'
Ms Guthrie said her family understands that their mother may be dead but that they want her to be brought home, regardless.
"For that reason we are offering a one million dollar reward for any information that leads up to her recovery," she said.
"Someone out there knows something that can bring her home.
"And we are begging you to please come forward now."
Ms Guthrie, an anchor on the NBC News morning show Today, has posted several video messages, along with her brother Camron Guthrie and sister Annie Guthrie, pleading for their mother's return and appealing for the public's help in solving the case.
Earlier in February, the FBI raised the reward they were offering for information to $US100,000.
Investigators have previously said that they had obtained a DNA sample from a glove that was found near the 84-year-old's Arizona home.
The FBI released door camera video footage on February 10, showing a person tampering with the camera.
The glove appeared to match the pair worn by a masked man seen in doorbell camera footage before she was abducted almost four weeks ago, according to investigators.
