MADRID (AP) — Interpol posted on its website Thursday the photographs of two Spanish children who allegedly were taken by their father from the Canary Islands off West Africa.

The international criminal police issued so-called “yellow notices” for the girls, ages 1 and 6. That step is taken to help locate missing persons, often minors, or help identify people who are unable to identify themselves, according to Interpol.

The girls, Anna and Olivia, and their father, Tomás Gimeno, went missing on April 27 in Tenerife, the largest of the Canary Islands.

Their mother, who is divorced from their father, alleges he told her she would never see him or her daughters again.

An official search began the following day on land and sea after Gimeno’s boat was found drifting in a Tenerife harbor with nobody on board.

The girls’ mother, Beatriz Zimmermann, earlier this week posted a video of her daughters in an effort to help find them.

A judge has ordered an information blackout on the investigation.