FBI investigators work the scene at First Baptist Church in Sutherland Springs, Tex., on Monday. (Scott Olson/Getty Images)

In the hours since a lone gunman opened fire at a church in Texas, killing 26 people in perhaps the deadliest mass shooting at a house of worship in modern U.S. history, political and spiritual leaders have been voicing concerns about safety in religious sanctuaries.

When the gunman, identified by authorities as 26-year-old Devin Patrick Kelley, went on a rampage Sunday at tiny First Baptist Church in Sutherland Springs, it was an armed civilian who returned fire. Kelley was found dead miles from the shooting scene; authorities believe he took his own life.

Some state and federal officials have since amplified calls for greater security measures in houses of worship as faith leaders, particularly throughout Texas, say churches are increasingly vulnerable.

“We are living in dangerous days,” Southern Baptist pastor Jack Graham said on Twitter. Graham, who serves as an evangelical adviser to President Trump, noted that “it is important that every church no matter how large or small have a security procedure.”

Graham said his Plano megachurch is preparing to “host and train church leaders for security training.”

Trump said the rampage “would have been much worse” if not for the armed citizen who “had a gun that was shooting in the opposite direction.”

Texas Attorney General Ken Paxton (R) told Fox News shortly after the shooting that lawmakers and law enforcement officials cannot necessarily keep guns out of the hands of people who are intent on breaking the law.

But, Paxton said, concealed-carry laws give citizens the opportunity to arm themselves and be in a position to help stop a gunman before first responders can get to the scene.

“We’ve had shootings at churches for forever,” the attorney general, who has advocated concealed-carry laws in the past, told Fox News. “It’s going to happen again, so we need people in churches — either professional security or at least arming some of the parishioners, or the congregation, so they can respond when something like this happens again.”

The deputy executive director of the Texas Democratic Party said Paxton should apologize for the comments.

“Something is woefully wrong when elected officials wring their hands and suggest we can only stay safe by bringing arsenals to church,” Manny Garcia said, according to the Dallas Morning News. “Texans deserve more from their chief law enforcement official than inaction and willful ignorance. The answer to horrific gun violence is not more of the same. Lord knows we have already had plenty of that.”

The Associated Press has tallied more than a dozen fatal shootings since 2012 at U.S. houses of worship.

Neo-Nazi Frazier Glenn Miller Jr. opened fire on a man and his 14-year-old grandson outside a Jewish center in April 2014 before driving to a Jewish retirement community, where he gunned down a woman visiting her mother.

The next summer, a white supremacist named Dylann Roof fatally shot nine black worshipers, including a pastor, at the historic Emanuel African Methodist Episcopal Church in Charleston, S.C.

After the weekend massacre in Texas, Ed Stetzer, executive director of Wheaton College’s Billy Graham Center for Evangelism, said many churches remain vulnerable and that congregations and faith leaders have to acknowledge that places where people gather are an easy target for those who want to commit violence.

“Every large church I know has a security ministry already,” he told The Washington Post. “I think more and more are going to do so. I think they’re going to, in some cases, have more than volunteers. I speak every week at a church in downtown Chicago … I assure you there’s not a Sunday when I don’t have within eyeshot several security team members.”

But, Stetzer said, “When you’ve got automatic or semiautomatic weapons, you’re talking about a whole different conversation. When you’ve got a crazy person with mental health problems … showing up in combat gear — I don’t know that security in most churches can handle something like that.”

Robert Jeffress of First Baptist Church of Dallas told “Fox & Friends” that as many as half of the members of his congregation bring their firearms into the church.

If shooters tried to open fire at his church, Jeffress said, “they may get one shot off or two shots off, but that’s it — and that’s the last thing they’ll ever do in this life.”

The Rev. Jamie Johnson, director of the Department of Homeland Security’s Center for Faith-Based and Neighborhood Partnerships, said the agency began teaching faith leaders and their congregations about safety and security measures long before the shooting in Texas.

Johnson, who was appointed by then-Homeland Security Secretary John F. Kelly in April, said his center has engaged with 1,500 religious leaders on issues of security at houses of worship. That includes speeches, exercises and training sessions during conferences and conventions, webinars and teleconferences.

“We provide active-shooter training, property management, from having more lights in parking lots to having more locks in doors,” he said. “We provide a perspective on reaching out to police leadership, fire leadership and emergency management services within their cities and counties. Wherever we go, we promote to pastors and spiritual leaders to reach out and begin to build personal contact with their chiefs of police, fire chiefs and city emergency managers.”

Johnson said the federal church security program was developed during the Obama administration and enhanced after Trump took office. The agency, he said, also gives guidance on how to provide security to churches of different sizes.

“You can’t compare a small church to a megachurch,” said Johnson, a member of the Anglican Church of North America. “We will coach houses of worship, whether they’re small, medium or large in size, to keep their property more secure and their membership safer, especially during regular weekly gatherings.”

Chuck Chadwick, who has been training churches to protect themselves for more than a decade through his security company and school, said that after a shooting or violent incident at a church, there is always an “uptick” in the number of churches seeking stronger security measures.

After Sunday’s incident, he said, his phone started ringing.

Chadwick, who founded the Dallas-Fort Worth-based National Organization of Church Security and Safety Management, has trained and certified more than 350 parishioners, church staffers and even pastors as personal protection officers at churches across Texas.

He said he uses a state-sanctioned program similar to one for private security officers — teaching hand-to-hand tactics, intermediate weapon use such as pepper spray or a baton, and handgun skills.

“I think it’s important to have an initial responder, a person who’s already trained and there,” he said.

He said that because most active-shooter situations are over in minutes, unless a church has armed law enforcement officers in the congregation or hired security personnel, it’s too late.

“So what we call the ‘initial responder’ person who’s already there is the person who needs to be able to take care of the situation immediately,” Chadwick said.

Johnson said more faith leaders will be more open to receiving practical training in the wake of the Texas shooting.

“The issue of safety and security for houses of worship,” he said, “is now at the forefront of America’s faith conversation.”

Read more:

Trump says Texas shooting is a problem of mental health, not guns

Who is Devin Patrick Kelley, the gunman officials say killed churchgoers in Sutherland Springs, Tex.?

An unlikely hero describes gun battle and 95 mph chase with Texas shooting suspect