A 5-year-old boy pulled out of a west side apartment complex swimming pool by his mother was in critical condition Friday night.

The woman and her son were in the gated pool area when she lost sight of her child, said Capt. Barrett Baker, a Tucson Fire Department spokesman.

She found her son at the bottom of the pool and she dove in and pulled him out, Baker said.

Several bystanders heard screaming and jumped the fence around the pool and began administering CPR. They continued until Tucson police and firefighters arrived shortly after 7 p.m. at the complex at 1001 W. Saint Mary's Road, said Baker.

Paramedics transported the boy to the hospital where he remained in critical condition, Baker said.

It was unknown how long the boy had been in the swimming pool, said Baker.

Baker said drowning is the No. 1 cause of unintentional death for children ages 1 to 4. He said children must be watched by an adult at all times when they are around water.