The UN says it has not yet seen evidence that the daughter of Dubai's ruler is alive, two weeks after seeking proof from the United Arab Emirates (UAE).
Princess Latifa Al Maktoum tried to flee the country in 2018. In a video, she claimed commandos drugged her as she fled by boat and flew her back to detention, reports the BBC.
Contact from her has since stopped. Dubai's royal family has previously said she is safe and being "cared for at home".
The footage of Princess Latifa prompted calls for a UN investigation.
Last month, the UN confirmed it had asked the UAE for proof that Princess Latifa was alive. But on Friday, it said that there had been no progress so far.
Spokesman Robert Colville said there had been meetings with the United Arab Emirates' diplomatic mission in Geneva, Switzerland, but when asked if proof of life had been received, he replied: "Not yet, no".
Latifa's father, Sheikh Mohammed bin Rashid Al Maktoum, is one of the richest heads of state in the world, the ruler of Dubai and vice-president of the UAE.