CALGARY -- The father of two young Cochrane, Alta. girls who haven't been seen for three days made an emotional plea Monday for information on their whereabouts.

Colin Zak is desperate to find his missing daughters, five-year old Leonine O'Driscoll-Zak and two-year-old Wyatt O'Driscoll-Zak, who were last seen Friday morning at their mom's home near Cochrane.

“I’m just so worried about my children,” said Zak.

“I don’t know where my girls are. I don’t know if they’re close to here if they’re far. We don’t know if they fled the country.”

Court documents describe a "high-conflict parenting dispute" following the couple's separation in 2019. 

Their father says the court ordered full custody of the kids to him on Friday but the girls were not returned.

“We thought we were finally going to get my children out of there,” said Zak.

“To find that they’re nowhere to be found, it’s devastating.”

The mother and sister of his ex are now suspected of taking Leo and Wyatt.

“Their disappearance is currently being investigated as an abduction involving their grandmother and their aunt,’ said Const. Shelley Nasheim with Parkland RCMP.

Both little girls are described as being slim with blue eyes and long, blond hair.

Leonine is about 121 centimetres (4') tall and 27 kilograms (60 pounds). Wyatt is about 91 cms (3') tall and 18 kilos (40 pounds).      

Their grandmother, Therese O'Driscoll is 68 years old with blue eyes, medium-length gray hair and is slim, about 157 cms (5'2") tall and 54 kgs (119 pounds). Their aunt, 38 year old Alison O'Driscoll has blue eyes, long brown hair, slim, 160 cms (5'3") tall and 54 kgs (119 pounds).

“There is definitely some custody issues,” said Nasheim. "At this time there’s no concern for the children safety it’s just that they need to check their welfare. It’s just a very volatile situation.”

Amber Alerts will only be issued if certain conditions are met, including if police believe abducted children to be in grave danger.

The Missing Children Society of Canada says alerts for child abduction evolve with police investigations, and amber alerts are sometimes triggered later in cases.

“As soon as they go missing from a safe place we need to come together as a community and find that child but police are determining how to best activate info into the community as they investigate,” said Amanda Pick the CEO of Missing Children Society of Canada.

“While you may see an Amber Alert not triggered initially, it may come hours later or a day later.”

The girls' father said he is concerned and gave a tearful plea.

“If you see them please call the police," he said. "Theresa and Alison please bring them home, please bring them home."

CTV had not spoken with the girls' mother, but their father said he got a call from RCMP saying they have interviewed mom, who says she doesn't know where the girls are.

Anyone who has tips on where these little girls or their grandma and aunt might be is asked to call Cochrane RCMP 403-851-8000 or Crimestoppers at 1-800-222-8477.

The Missing Children's Society also launched an app recently where you can get updates and submit tips right through the app.

You can download the app here.