(CNN) -- Authorities will resume their search Monday morning for the bodies of four men who are believed to have drowned in southeastern Idaho after one of them fell overboard and three others went missing trying to rescue him, the Power County Sheriff's Department said.
"It is not confirmed they are deceased at this time -- presumption that they are -- but we cannot confirm any deaths at this time or drowning," said Cpl. Leilani Morgan.
The incident took place Sunday at the American Falls Reservoir, about 180 miles east-southeast of Boise.
Five children -- all under the age of nine -- also were on the boat and have been rescued by authorities, according to the sheriff's department.
CNNRadio's Matt Cherry contributed to this report