The ex-wife of a nephew of the ruler of Dubai has been taken into custody, authorities have said, as a custody battle over their three young daughters deepens.

Dubai Public Prosecution told the BBC that Zenab Javadli was detained following a complaint made by the father of her three children - her former husband, Sheikh Saeed bin Maktoum bin Rashid Al Maktoum.

Javadli's family and friends had lost contact with her since Tuesday night and had raised the alarm over her whereabouts.

For almost two days, no news was received as to where Javadli or her children had gone.

For months, she had barely left the house as she believed security officers were waiting to take her children from her and put her under arrest.

According to Dubai Public Prosecution, her ex-husband has alleged she abducted the children during a court-approved visitation session.

Last year, he lodged a complaint with the police accusing her of kidnapping their daughters.

That was after the children changed hands between their parents several times, with each accusing the other of kidnap.

Javadli - a former international gymnast - has also been facing potential arrest for e-crimes - online offences - in the UAE after she livestreamed one of the showdowns last year.

At the time she explained her actions in a video message to the British human rights lawyer David Haigh, who has been advocating for her: "I knew that it was the last chance to be with my children as they would never let me see them again. I genuinely believed that it was my last chance, so I just opened a livestream and called for help."

Lawyers acting for Sheikh Saeed bin Maktoum bin Rashid Al Maktoum have claimed in court hearings in the custody case over their children that she was an unfit mother who had failed to send her daughters to school, was living in a place unsuitable for the children when she was in a hotel, and that she had put the health of the youngest girl at risk.

In a statement on Thursday evening, Dubai Public Prosecution said the matter remained under investigation and was subject to ongoing legal proceedings.

"[We] will continue to take the necessary legal measures in accordance with applicable laws, while safeguarding the children's wellbeing and best interests," it added.

In response, Haigh called on the UAE to immediately grant Javadli access to her lawyer, her consulate and her family and be released back to her home in Dubai.