Discuss as:

3 children electrocuted while swimming in lakes; 3 drown in river

Saul Young / AP

Evidence tape covers an electrical meter near two houseboats at German Creek Marina on Cherokee Lake in Bean Station, Tenn., on Wednesday. One boy died and another was critically injured after an apparent electrocution.

Updated at 8:40 p.m.: Three children died -- two in Missouri and one in Tennessee -- after they were shocked by electricity while swimming in lakes, authorities said.

In another tragedy, three children drowned in the Iowa River, police said.

In Missouri, 13-year-old Alexandra Anderson and her 8-year-old brother Brayden of Ashland were killed when they were shocked around noon by an unknown source of electricity while swimming near a private dock in the Lake of the Ozarks, KSHB-TV reported

Several adults got the siblings out of the water but couldn't revive them. They were pronounced dead at Lake Regional Hospital in Osage Beach.

The Missouri Highway Patrol said investigators were looking at electricity powering lights and a pump that supplies water to a slide children use at the dock, but they had not determined what had caused the electrocution by Wednesday evening.

The accident in Tennessee happened near the German Creek Marina on Cherokee Lake in the town of Bean Station. Two boys were swimming in the lake between two house boats when they were shocked, the Grainger County Sheriff's Office said, WBIR-TV reported.

Saul Young / AP

The scene at German Creek Marina on Cherokee Lake in Bean Station, Tenn., on Wednesday after a boy died and another was critically injured in an apparent electrocution.

Both boys, whose names were not released, were originally reported dead, but Sheriff Scott Layel said one child was revived on a medical helicopter flight.

The sheriff's department said several other people were taken to the hospital in Morristown to be checked out because bystanders trying to rescue the boys were shocked as well.

The marina was evacuated as a precaution. Authorities were searching for the source of the electric current. 

Layel told the Knoxville News Sentinel that wiring in the bottom of one of the houseboats might have caused the shocks.

It was uncertain whether the boys were shocked in the water or when they touched the metal ladder of one of the houseboats, Layel said.

A visitor from California, Paul Worley, told WBIR that he was temporarily paralyzed when he jumped into the water to try to rescue one of the victims.

"We heard the screaming, and we ran down there and saw a kid and a lady in the water," Worley told WBIR from his hospital bed in Morristown.

He said he jumped into the water not knowing it was electrified.

"I went down about 3-4 feet, and I figured 'I'm dead' because by then, I knew what it was."

He said despite the shock he tried to get one of the children to a nearby jet ski.

"I know when they cut off the electricity from the boat. I didn't feel the electricity anymore," he said.

WBIR said Worley was expected to be released from Lakeway Regional Hospital Thursday.

Drowning claims three other children
In another incident, the bodies of three children were found in the Iowa River Wednesday night near Marshalltown, NBC station WHO of Des Moines reported.

The station said the children were reported missing around 6:30 p.m. and the bodies of two girls and one boy, ages 6-10, were found just before 9 p.m. Police say the children were swimming in the river. 

More content from msnbc.com and NBC News:

Follow US News on msnbc.com on Twitter and Facebook