Terrified clergy members hid behind an altar when a 16-year-old boy with a gun disrupted a Louisiana church during a First Communion ceremony and was confronted by parishioners and arrested by police.

The stunning scene was caught on camera during a livestream of the Saturday morning service at St. Mary Magdalen Church in Abbeville, about 125 miles west of New Orleans.

Witnesses said the teen was dressed in black and carrying a rifle when he tried to enter the Catholic church, where 60 children were making their first Holy Communion, local TV station KADN reported.

The Rev. Nicholas Dupre was about 45 minutes minutes into leading the service when a man approached the altar and whispered into his ear, KADN said.

Dupre then told worshippers to sit and began leading them in recitations of the Hail Mary prayer.

But after screams and shouts erupted at the rear of the church, Dupre and two other clergy members crouched behind the altar as a police officer with a rifle emerged.

"We did apprehend a young man," an officer later told the crowd. "He is in custody. Calm down and get next to your child and just go slowly."

The disturbing incident took place less than a week after another gunman allegedly tried to kill the pastor of the Jesus' Dwelling Place church in North Braddock, Pennsylvania, outside Pittsburgh, as he delivered a sermon on May 5.

"He pulled the gun; it clicked," the Rev. Glenn Germany said afterward. "God jammed the gun so the bullet didn't come out."

In a statement posted on Facebook, Abbeville Police Chief Mike Hardy said the department received a call around 10:35 a.m. about a suspicious person with a gun at the Louisianna church who was "confronted by parishioners and escorted outside."

"Upon arrival, officers arrested the suspect and placed him in custody," Hardy wrote.

No one was injured and Abbeville officers and deputies from the Vermilion Parish Sheriff's Office swept the church to make sure there were no additional threats.

The unidentified teen was questioned by police in the presence of a parent and was taken for evaluation at the Abbeville General Hospital's behavioral unit, Hardy said.

The boy is being charged with terrorizing and two counts of possession of a firearm by a juvenile, Hardy said.

In a statement, St. Mary Magdalen Church said the incident "understandably caused panic," and said it was "incredibly grateful to both parishioners and police officers for acting quickly to ensure the safety of all."

Bishop J. Douglas Deshotel of the Diocese of Lafayette also said: "The quick response of the Abbeville Police Department and alert parishioners is a great example of caring for the most vulnerable in our community. Let us pray for an end to all threats of violence to innocent human life."