Investigators now believe that last week's raid by suspected jihadis in Burkina Faso led to the abduction of around 60 women, girls and babies, a regional prosecutor said Thursday.

Earlier reports had suggested that around 50 women had been taken, said a statement from the prosecutor for the northern Djibo region, Issouf Ouedraogo.

But police now think that girls and newborns were among those abducted, he added, announcing the opening of a new investigation.

On Wednesday, the Burkinabe Movement for Human Rights said it had drawn up a "non-exhaustive" list of 61 women it said had been abducted, which included at least 26 who were younger than 18.

The organization called on the authorities to do more to protect people living in the threatened regions, including ensuring access to humanitarian aid.

The victims of the abductions were seized while out gathering wild fruit and other food, the prosecutor's statement added.

Jihadis regularly prey upon the town of Arbinda, near where the women and children were taken. It was the increasingly scarce deliveries of supplies to the town that drove the women to venture out to forage.

On Monday, Rodolphe Sorgho, the lieutenant governor of the Sahel region, said search teams were operating on the ground and in the air to try to trace the group.

Jihadis from both the Islamic State group and al-Qaida have been raiding Burkina Faso, particularly the northern half of the country, since 2015.

During that period, their attacks have killed thousands and driven at least 2 million others to flee their homes.