08/05/2014 08:40 EDT | Updated 10/05/2014 05:59 EDT

Girls, 9 And 10, Missing From Aird Lake Cottage Overnight

Paul Stainthorp/Flickr
Playing hide-and-seek. Woodhall Spa, Lincolnshire. 4 March, 2011

UPDATE: The missing girls have been found in good health, according to the Ontario Provincial Police.

Two girls aged nine and 10 years old are missing after failing to return to their family cottage in the Township of Greater Madawaska in eastern Ontario following a game of hide and seek Monday night.

The girls had been staying at their family's cottage near Aird Lake, on Airds Lake Road, about an hour's drive southwest of Calabogie, Ont.

The names of the girls and the family haven't been released.

They were last seen after 8 p.m. ET by relatives who were playing a version of hide and seek with the girls, said Jenelle Rosenblath, who owns a camping site on Airds Lake Road.

"Nobody's heard or seen anything from the girls since," Rosenblath said. "... It's an awful thing, but we're still hopeful."

'Everybody's just walking on eggshells'

The girls were wearing pyjama bottoms and sweaters, said Rosenblath, who added it was cool and damp in the area overnight.

"Everybody's just walking on eggshells," she said. "It's a thick terrain, and they sat out all night. As the night went on, you just got more anxious and more hopeful."

Ontario Provincial Police arrived at about 10 p.m. to begin their search. 

Patrol officers, canine units and an emergency response team spent the night looking through the area.

An OPP helicopter and additional canine units are on the way Tuesday morning, OPP said on Tuesday morning.