Thai police will carry out DNA tests on nine babies found in mysterious circumstances in a Bangkok apartment - each with a supposed nanny - to determine the identity of their parents.
The discovery follows a scandal that erupted after an Australian couple were accused of abandoning a baby boy with Down syndrome born to a Thai surrogate Pattaramon Chanbua, while taking home his twin sister.
There were no documents found with the nine babies, leading authorities at the emergency accommodation where they are being cared for to guess they are aged between two weeks and two years old.
A Thai lawyer who was at the apartment at the time of Wednesday's raid deepened the mystery by telling police that all nine babies were the children of an unnamed wealthy Japanese man.
Also present at the plush condominium in a city suburb were nine nannies and a pregnant woman, who later said she was acting as a surrogate mother.
The nannies told authorities they were paid $US310 a month to look after the children.
It was not immediately clear if the babies were also born to surrogate mothers.
Police said it could take weeks to prove who their biological fathers and mothers are.
Thai authorities have stepped up their scrutiny of surrogacy in the kingdom, following the controversy involving the Australian couple who have denied they rejected the Down's syndrome baby - a seven-month-old named Gammy.
The surrogate mother Ms Chanbua said she agreed to carry another Thai donor's egg fertilised by the Australian man in exchange for around $US14,900.
The man, 56, has been exposed as a convicted paedophile in Australia.
Thai medical officials say surrogacy is illegal - unless it is with a relative - in the kingdom and offering money to carry a baby is prohibited.
There are 45 public and private surrogacy clinics in the kingdom and 240 doctors certified to carry out procedures.
In the wake of the baby Gammy scandal, Thailand's new junta rulers have vowed to beef up punishments and close current loopholes which they say are being exploited by foreigners seeking Thai surrogates.