At least four people drowned on Sunday while swimming in an Arizona river when the group was overwhelmed by a surge of flood water that followed heavy rains in the drought-stricken region, the Gila County Sheriff's Office said on Facebook on Sunday.
The reports cited the sheriff, who could not be reached immediately to confirm the number of fatalities.
In the statement posted on Facebook, Sheriff J. Adam Shepherd said a search-and-rescue operation was underway for the missing.
Meanwhile, there was concern for possible flash flooding in southern Arizona, as well.
The National Weather Service in Phoenix said that most of Arizona was under flash flood watch until Monday evening, warning that "heavy rains can produce flash flooding of low lying, normally dry areas such as washes."
Reporting by Bernie Woodall in Fort Lauderdale, Florida; Editing by Frank McGurty and Sandra Maler