UPDATE: RCMP have announced that the Amber Alert has been cancelled, as of Monday morning. The girl was located safely.

North Battleford, Sask., RCMP have issued an Amber Alert for a six-year-old girl.

Police said they believe a car with the girl inside was stolen after the mother left it unlocked and running outside a strip mall at 11204 Railway Ave. in North Battleford at around 5 p.m. CST Sunday.

The direction of travel of the car is unknown, but police have expanded the search to Manitoba and Alberta.

She has epilepsy and autism, and police say she is non-verbal and can walk, clarifying an earlier report that she is unable to walk. Police said she is on medication for epilepsy that needs to be taken "in a strict timeframe" every 12 hours, and that missing a dose could lead to extreme medical distress. It's unclear if she has access to her medication.

When last seen, the girl was wearing a diaper, and also:

Has brown, chin-length hair.

Is 3-foot-6 and weighs 44 pounds.

Was wearing a navy-blue, long-sleeve T-shirt, black jeans and pink socks.

Wasn't wearing shoes.

"We just need her back," the girl's parents said in a video posted on Facebook by the Saskatchewan RCMP.

RCMP Cpl. Rob King had a message for the person who stole the car: "Bring her back. Quite simply. Bring her to the nearest detachment…. Contact 911 yourself. Do whatever you can to get her back."

Police said highly trained investigators have been deployed to the North Battleford area and the RCMP Major Crime Unit is leading the investigation. Additional resources have also been deployed: A helicopter from Alberta RCMP and airplane from Saskatchewan RCMP are on standby in the event a search location is identified.

Police said the vehicle has a keyless system so when stopped, it would be immobilized. They believe there was half a tank of gas left in the car when it was taken.

There's no description of the person suspected to have taken her, but the person is believed to be driving a dark grey 2010 Mercedes-Benz GL350 Bluetec SUV, with Saskatchewan licence plate 897 HMX.

Police are asking gas stations across Western Canada to be on the lookout for this stolen SUV as the vehicle may attempt to stop and fill up at some point.

'Keep looking'

Krista Clark, a friend of the family, told CBC News that previous claims the girl can't walk are not correct.

"She can walk," Clark said. "She can move about freely. At home she walks from room to room.… They have to barricade the Christmas tree so that she doesn't take things she shouldn't have."

Police said they don't believe the girl could free herself from a car seat, but Clark said she's concerned.

"If she were to be removed from the vehicle and left on the side of the road, she would wander in any direction, into the road, into a field."

Clark also said the six-year-old doesn't respond to her name.

"If she were seen and people called out ... she wouldn't respond to it necessarily and she is not able to say that she needs help or that she doesn't know where she is."

The girl laughs when she's entertained and cries if she's upset, and can communicate non-verbally with family members, but is unable to speak.

If she were seen and people called out ... she wouldn't respond to it necessarily. - Krista Clark, family friend

Clark's main concern is that the child is brought home safely.

"Everyone we know in North Battleford is out looking right now for her."