A Saudi woman held at Bangkok airport said she would be killed if she was repatriated by Thai immigration officials, who confirmed the 18-year-old was denied entry to the country on Sunday.
The incident comes against the backdrop of intense scrutiny of Saudi Arabia over its investigation and handling of the shocking murder of journalist Jamal Khashoggi last year, which has renewed criticism of the kingdom's rights record.
Rahaf Mohammed al-Qunun told AFP she was stopped by Saudi and Kuwaiti officials when she arrived in Suvarnabhumi airport and her travel document was forcibly taken from her, a claim backed by Human Rights Watch.
"They took my passport," she told AFP, adding that her male guardian had reported her for travelling "without his permission".
Qunun said she was trying to flee her family, who subjected her to physical and psychological abuse.
"My family is strict and locked me in a room for six months just for cutting my hair," she said, adding that she is certain she will be imprisoned if she is sent back.
"I'm sure 100 per cent they will kill me as soon as I get out of the Saudi jail," she said, adding that she was "scared" and "losing hope".
Qunun was stopped from entering Thailand when she flew in from Kuwait on Sunday, Thailand's immigration chief Surachate Hakparn told AFP.
"She had no further documents such as return ticket or money," he said, adding that Rahaf was currently in an airport hotel.
"She ran away from her family to avoid marriage and she is concerned she may be in trouble returning to Saudi Arabia. We sent officials to take care of her now," he said.
He added that Thai authorities had contacted the "Saudi Arabia embassy to coordinate".
But Qunun disputed his account, saying that she was only in transit to seek asylum in Australia, and was accosted by Saudi and Kuwaiti embassy representatives when she arrived at Suvarnabhumi airport.
She took to Twitter to plead her case, creating a profile with an Arabic bio that reads "I just want to survive".
During a video livestream showing her walking around a carpeted hallway, Qunun spoke in Arabic about how her father had told Saudi embassy officials she was a "psychiatric patient" who had to be returned, even though she had "an Australian visa".
"I can't escape the airport," she said in the live video. "I tried but there's a security (official) watching me."
In a sign of growing desperation over the last few hours, the woman live tweeted barricading her hotel room door with furniture.
Immigration head Surachate said Qunun would be sent back to Saudi Arabia by Monday morning.
"It's a family problem," he said of the case.
But Human Rights Watch said Thai authorities must allow the teenager to make a refugee claim with UNHCR, the United Nations refugee agency.
"Saudi women fleeing their families can face severe violence from relatives, deprivation of liberty, and other serious harm if returned against their will," said Michael Page, HRW deputy Middle East director.
"Thai authorities should immediately halt any deportation, and either allow her to continue her travel to Australia or permit her to remain in Thailand to seek protection as a refugee."
Abdulilah al-Shouaibi, charge d'affaires at the Saudi embassy in Bangkok, acknowledged the woman's father had contacted the diplomatic mission for "help" to bring her back.
But in an interview with Saudi-owned channel Rotana Khalijial, he denied that her passport had been seized and that embassy officials were present inside the airport.
Saudi Arabia has come under fierce criticism following the murder of dissident journalist Khashoggi inside the kingdom's Istanbul consulate on October 2 -- a case that stunned the world.
The ultra-conservative kingdom has long been attacked for imposing some of the world's toughest restrictions on women.
That includes a guardianship system that allows men to exercise arbitrary authority to make decisions on behalf of their female relatives.
In addition to facing punishment for "moral" crimes, women can also become the target of "honour killings" at the hands of their families, activists say.