Hathloul was arrested along with around a dozen women activists in May 2018
Jailed Saudi women's rights activist Loujain al-Hathloul has begun a new hunger strike in prison to demand regular contact with her family, her siblings said on Tuesday.
Hathloul, whose detention since 2018 has made her emblematic of the fight for women's rights in Saudi Arabia, began refusing food on Monday evening, her sister Lina al-Hathloul said.
"Loujain told (our parents) she is exhausted of being mistreated and deprived from hearing her family's voices," Lina wrote on Twitter.
"She told them she will start a hunger strike starting yesterday evening until they allow her regular calls again."
There was no immediate comment from Saudi authorities.
Hathloul's parents were allowed to see her on Monday, her siblings said, but for months the activist has been permitted only limited contact with her family.
In August, Hathloul went on a hunger strike for nearly a week after she was denied the right to call or meet her family for several months, her siblings said.
She ended that strike after her parents were eventually allowed to visit her in prison, they added.
Hathloul, 31, was arrested along with around a dozen women activists in May 2018, just weeks before Saudi Arabia lifted a decades-old ban on female drivers.
Some of them have been provisionally released, while others including Hathloul remain in detention amid what campaigners call opaque court trials over charges that include contact with foreign media, diplomats and human rights groups.
The pro-government media branded Hathloul and other jailed activists as "traitors" and her family alleges she faced sexual harassment and torture, including electric shocks and water boarding, in detention.
Hathloul also accused former royal court media adviser Saud al-Qahtani of threatening to rape and kill her, according to her family.
Saudi authorities vigorously deny the charges.
The detention of women activists has cast a spotlight on the human rights record of the kingdom, which has also faced intense global criticism over the 2018 murder of journalist Jamal Khashoggi in its Istanbul consulate.
This month, European lawmakers passed a wide-ranging resolution calling on the European Union to downgrade its attendance at next month's G20 summit in Riyadh over human rights concerns.