Born eight weeks premature and requiring round-the-clock care, the child, named only as Santiago, was found by police at an Amsterdam hotel in the Netherlands along with his parents on Friday.

“The information is rather reassuring about his state of health,” Belgian prosecutor Vincent Macq said on Saturday.

Belgian authorities have been involved in the search as Santiago’s parents are thought to have fled from France to Belgium before reaching the Netherlands.

French authorities had issued European arrest warrants for the parents, who were detained by Dutch police on Friday evening.

The arrest went “smoothly”, Macq told a press conference in the western city of Mons.

Santiago’s grandmother and two other children, one believed to be the child’s sister and the other yet to be identified, were also at the Amsterdam hotel at the time of the arrest, he said.

Dutch authorities, which earlier said the baby was receiving care in hospital, were now in charge of the case, Macq added.

Late on Monday evening – just 17 days after his birth – Santiago’s parents aged 23 and 25 took him from the neo-natal unit in the Robert Ballanger hospital in Aulnay-sous-Bois, northeast of Paris.

Authorities appealed to the public for information with a nationwide kidnapping alert.

The motive for their flight was not yet known but investigators said it was likely the parents feared they could lose custody of the baby.