A sheriff's officer who threw off his gear and dived into a frozen pond to save an 8-year-old Utah boy on Christmas Day refused to be labeled a hero on Tuesday.

The officer, Washington County sheriff's Sgt. Aaron Thompson, arrived at the frozen pond in New Harmony, in the southern part of the state, after the boy's friend called for help late Monday afternoon, authorities said.

The boy, whose name hasn't been made public, was chasing his dog when he fell through the ice, authorities said. His condition hasn't been disclosed. Thompson suffered only cuts, bruises and symptoms of hypothermia, and he was back at work Tuesday.

"You never know exactly what you're going to get into," Thompson, a rescue diver by training and a former member of the sheriff's dive team, told reporters on Tuesday. "I just made the decision that I was going to go get him."

Thompson said he walked out on the ice a few feet and started to pound on it with his hands, but "the ice got thicker, and I couldn't break it with my arms and my fists."

"So I started to jump up and down on it using my body weight," and it eventually gave way, he said

He then dived to the bottom to assess the temperature and clarity of the water. All of the signs were promising, he said, because "the clearer the water, the colder the water, the younger the individual," the better chance you have of rescuing someone alive.

At one point, he did begin to get desperate, Thompson said.

Search-and-rescue workers at a frozen pond Monday in New Harmony, Utah, where a sheriff's sergeant rescued a drowning 8-year-old boy. Washington County Sheriff's Office

"I had searched the entire broken-out area," he said, but it turned out that the boy was back beneath the unbroken ice.

"Using my tippytoes, walking in the water up to my neck ... I knew eventually I was going to bump into him," Thompson said.

Thompson said he believed the boy had been in the water for about 30 minutes, adding that "as a water rescuer, we're trained to know we have a 'golden hour.'"

"The temperature of the water was a huge, huge factor," he said. "We're really hopeful for this individual."

Asked how felt about being proclaimed a hero, Thompson said other rescue workers were ready to go in to the water, too. He just happened to be the first one there.

"It's not me. It's us," he said, championing the involvement of medical crews, the helicopter crew and a witness who steered him in the boy's general direction, as well as members of other agencies who all flocked to the scene.

"That's the real story here," he said. "I was just the one that went out into the water."