ALABAMA, United States (AP) — A 71-year-old man fatally shot two elderly people and wounded a third with a handgun during a potluck dinner at an Alabama church where he occasionally attended services, police said Friday.

The suspect was subdued and held by an attendee of the event until police arrived Thursday evening, sparing the congregation from further violence at St Stephen’s Episcopal Church in the Birmingham suburb of Vestavia Hills, Police Captain Shane Ware said.

“It was extremely critical in saving lives,” Ware told a news conference. “The person that subdued the suspect, in my opinion, was a hero.”

Ware did not give a motive for the shootings. He also didn’t identify the suspect, whom police took into custody at the church. He said the man’s name was being withheld until prosecutors formally charge the man with capital murder.

Walter Rainey, 84, of nearby Irondale was killed at the church and Sarah Yeager, 75, of Pelham died after being taken to a hospital. The third victim, an 84-year-old woman, remained hospitalised, Ware said.

He said the suspect and the three victims were all white.

The event was a “Boomers Potluck” gathering inside the church, according to messages posted on the church’s Facebook page by the pastor, Rev John Burruss. He said he was in Greece on a pilgrimage with a group of members and trying to get back to Alabama.

Police are still trying to determine the shooter’s motive, Ware said. He said the suspect had previously attended services at the church.

Vestavia Hills Mayor Ashley Curry praised the police response, saying officers “handled this crisis in an exemplary manner”. He said his “close-knit, resilient, loving community” of 39,000 had been rocked by “this senseless act of violence”.

The Rev Rebecca Bridges, the church’s associate rector, led an online prayer service on the church’s Facebook page Friday morning. She prayed not only for the victims and church members who witnessed the shooting, but also for the person who perpetrated the shooting.

“We pray that you will work in that person’s heart,” Bridges said. “And we pray that you will help us to forgive.”

Bridges, who is currently in London, alluded to other recent mass shootings as she prayed that elected officials in Washington and Alabama “will see what has happened at St Stephens and Uvalde and Buffalo and in so many other places and their hearts will be changed, minds will be opened”.

“And that our culture will change and that our laws will change in ways that will protect all of us,” she added.

There have been several high-profile shootings in the United States May and June, starting with a racist attack on May 14 that killed 10 black people at a supermarket in Buffalo, New York. The following week, a gunman massacred 19 children and two adults at an elementary school in Uvalde, Texas.

Thursday’s shooting happened just over a month after one person was killed and five injured when a man opened fire on Taiwanese parishioners at a church in Southern California. It comes nearly seven years to the day after an avowed white supremacist killed nine people during Bible study at Emanuel AME Church in Charleston, South Carolina.

Agents with the FBI, US Marshals Service and the Bureau of Alcohol, Firearms, Tobacco and Explosives joined investigators at the scene, which remained cordoned off Friday with yellow police tape as police vehicles with flashing lights blocked the route to the church.

On Saturday, thousands of people rallied in the US and at the National Mall in Washington, DC, to renew calls for stricter gun control measures. Survivors of mass shootings and other incidents of gun violence lobbied legislators and testified on Capitol Hill earlier this month.

Alabama Governor Kay Ivey issued a statement late Thursday lamenting what she called the shocking and tragic loss of life. Although she said she was glad to hear the suspect was in custody, she wrote: “This should never happen — in a church, in a store, in the city or anywhere.”

Vestavia Hills is a residential community just southeast of Birmingham, one of Alabama’s two most populous cities.