Image copyright First United Methodist Church / Facebook

A man accidentally shot himself and his wife during a discussion on gun safety at a Tennessee church, police say.

The 81-year-old took out his pistol to show another parishioner amid a talk about recent shootings at places of worship.

Forgetting the weapon was loaded, he fired a single round, striking himself in the hand and his 80-year-old wife, who was sitting in her wheelchair.

Both suffered non-life-threatening injuries, police said.

The incident happened on Thursday afternoon as a Bible-study group met for a pre-Thanksgiving lunch at the First United Methodist Church in the town of Tellico Plains.

A parishioner who only wished to give her first name, Mistin, told the BBC that the congregants had been talking about a Texas church massacre earlier this month.

"The discussion of guns in churches came up," she said. "Should we have guns in churches, if people carry guns should they bring them to church?"

She said one of the parishioners mentioned that he carries his pistol with him everywhere.

The man produced the handgun from his pocket, removed the magazine, and handed it to other churchgoers to inspect.

He then took his weapon back, restored the magazine, holstered the weapon and put it back in his pocket, Mistin said.

Another parishioner later asked to see the weapon.

The man produced the gun and accidentally pulled the trigger.

"They heard a big explosion," said Mistin. "Wasn't sure what it was, and Miss Nicole looked at Miss Catherine, and Miss Catherine looked at her and she said, 'I've been shot.'"

The bullet hit the gun-owner in the right hand before piercing his wife's abdomen and exiting through her right forearm, ricocheting off the wall and landing by her wheelchair, according to police.

Mistin said the man may have lost his thumb.

His wife is in surgery, but is expected to survive.

Tellico Plains Police Department Chief Russ Parks said no one else was injured and no charges will be filed.

"This was an accident. It was not intentional," Chief Parks told ABC News.

"It just slipped his mind that he recharged the weapon."

Mistin said the injured man is a lifelong gun-owner who practises every week.

But she said he's been so traumatised by the incident that he plans to get rid of his weapons.

"They're just true servants of the Lord, they're such a delight," she said of the couple.

"We thank God. I don't know how God's using this but we put it in His hands."