A man reportedly drowned after falling from a bridge trying to save his three-year-old son.

Christopher Schultz jumped from a bridge in Detroit Lakes, Minnesota, after his child fell into the water, according to police.

The 31-year-old began to struggle while keeping the child above water, Becker County Sheriff's Office said.

Bystanders went into the lake and brought the child to shore, but Schultz never resurfaced, Sheriff Todd Glander said.

Authorities received reports of a drowning at around 8.22am at Long Bridge at Dead Shot Bay on Saturday night.

Christopher Schultz died saving his three-year-old child from the water after the boy fell into a lake in Minnesota

The bridge in Detroit Lakes, Minnesota, where father Christopher Schultz jumped in to save his young son

Emergency services searched for him and found the father-of-four with the help of fisherman at 9.07am when he was rushed to hospital but pronounced dead.

Last night investigators identified the man as 31-year-old Christopher Franklin Nicholas Schultz of Frazee, Becker County.

Bill Wickum, who lives in Detroit Lakes, said the area where the youngster fell in is the water is dangerous, but not that deep for an adult to navigate.

He told Fox 2 Detroit: 'You're a father you're going to do anything you can to save the kid.

'It is deep, there is a current, but it's fairly close to where you can touch - five strokes to where you can probably hit bottom.'

Wickum reflected on Schultz's sacrifice for his son, the day before Father's Day.

He added: 'He [Schultz] made the ultimate sacrifice for his son, and I hope his son grows up to be a worthy recipient of that because you can't think of any greater sacrifice. So, that's a sad, sad, story.'

Schultz with his son. He managed to hold the boy above the water so bystanders could rescue him from the Minnesota lake

The three-year-old boy fell from this bridge in Detroit Lakes. Schultz was described as a hero for saving the toddler from the water

Schultz died at a hospital in the city of Detroit Lakes, about 45 miles (70 kilometers) east of Fargo, North Dakota.

The three-year-old boy was treated for non-life threatening injuries at hospital but is expected to be survive, authorities said.

Matthew Clark described his friend as a hero for saving the toddler.

He wrote on Facebook: 'Rest in Peace Topher Schultz. I am beside myself upon hearing the news. you saved your childs life.

'You're a hero. you always been a stand up guy to me and i always enjoyed our convos. you where a funny and fun person. you will be missed by many.'

The Detroit Lakes Fire Department, Minnesota State Patrol, and Minnesota DNR were at the scene and the incident remains under investigation, authorities said.

Clark told KVLY-TV: 'Without a hesitation jumping in - that's heroic, to me that's an honorable death.

'Guy just sacrificed his life to make sure his kid could see another day. He wasn't thinking about anything else other than that.

'I really feel for the kids because when they're calling for daddy they're not going to understand why he's not going to be able to come home.'

A GoFundMe page set up to help pay for funeral costs and medical bills has so far raised $1,245 for Schultz's family.