Three children have died after being electrocuted while swimming on the Fourth of July, while another three youngsters were killed after drowning in a river during the holiday celebrations.

In separate lake tragedies during the nationwide U.S. celebrations, three children were killed by electric currents in Missouri and Tennessee, while three young siblings drowned in a river in Iowa.

Alexandra Anderson, 13, and her eight-year-old brother Braydon were killed by an ‘unknown source of electricity’ in the Missouri lake yesterday.

Police say the children were swimming near a private dock on the Lake of the Ozarks when they were shocked by an ‘unknown source of electricity’ just after noon.

Adults standing on a dock heard screaming and jumped in. Police say those who jumped in felt electricity and cut off power to the dock. The adults got the children out of the water and immediately began CPR, but it was too late.  

Investigators were looking at electricity powering lights and a pump used to supply water to a slide on the lake.

In a separate accident in eastern Tennessee a ten-year-old boy was electrocuted and his 11-year-old friend seriously injured after jumping into Cherokee lake off a docked houseboat.

Five people who tried to help the children were also shocked at the German Creek Boat Dock in Bean Station, where two families were celebrating Independence Day on a houseboat, officials said.

‘People on board the houseboat heard some screams and found the two boys floating in the water, with their life jackets on, unconscious,’ said Matt Cameron, a spokesman for the Tennessee Wildlife Resources Agency.

It was originally reported that both boys, whose names were not released, had died but one child was resuscitated as he was airlifted to hospital.

In another incident, police in Marshalltown, Iowa, recovered the bodies of three young children who drowned in a river during the celebrations.

The seven and nine-year-old girls found on Wednesday night in the Iowa River, as well as a seven-year-old boy, were said to be family members. 

They were swimming together in a wooded stretch of the river near Riverview Park north of town when they disappeared.

One of the families are believed to be Burmese.

Authorities searched the river for more than three hours after they were separated from others who were swimming.

Marshalltown Police Chief Mike Tupper said drought has left the river shallow. There are places where it’s only ankle deep, but other pockets of 12-plus feet of water and so swimming should be avoided.

He said: ‘The message that we are trying to get out to people is that the river is not a safe place to be, it’s not a safe place to swim. The river looks relatively calm down on the location where this occurred, and in many areas down there, it’s very shallow. 

‘But there are also areas that can drop off to 12 or 14 feet, and the undercurrent can be very dangerous in any river.’

Chief Tupper told the Des Moines Registry the search was difficult because boats could not be used. Shallow waters and steep banks kept authorities from putting boats in at useful locations. Most of the searching was from the banks.

This is not the first time Iowa waters have been deadly to swimmers and boaters. On June 18, Andres Favela, ten, drowned after jumping into the river less than a mile from where yesterday’s tragedy occurred. 

Around the same time, a teenager drowned at a West Des Moines park and an Ames police sergeant drowned while trying to reach his daughter in a wayward boat.

The state is on pace for its deadliest summer boating season in recent years, with seven boating-related fatalities so far.

Elite.