Siblings drown playing breath-holding game

A young brother and sister competing to see who could hold their breath the longest have drowned while their foster parents watched on unaware.

The four-year-old boy and his six-year-old sister were swimming in Lake Georgetown, Texas, about 45m away from their parents when their game turned deadly on Sunday.

They were found about 5m from the shoreline in water less than 1m deep by another child, aged 12, who went to investigate after noticing something was not right, Fox News reports.

Police said they did not expect the foster parents to face any criminal charges following the deaths but they have had two other children removed from their care.

"It's horrible, it's tragic," said Julie Moody of the Texas Department of Family and Protective Services, which is investigating the foster parents.

The names of the children have not been released.

Source: Fox News.