A 3-year-old, Oahu boy was in serious condition after he was pulled from Waimea River Saturday afternoon on Oahu’s North Shore.

Lifeguards had warned the gathering of adults and children not to venture into the river but were ignored, said Jim Howe, operations chief for the city’s Ocean Safety division.

"We’ve been cautioning people about going into that river," Howe said. "The river’s not running, but it drops off real rapidly behind a steep bank. It’s not a swimming pool."

The parents had been taking shifts watching the children play in the river, Howe said, and one woman went to get another woman to take over around 3:15 p.m.

"In just the minute that she was gone, that’s when the boy went under," Howe said. "Another mom came back to take over and went into the water and kicked him. That’s how she found the little boy on the bottom."