A fire early Saturday morning at a Roman Catholic church in El Paso, Texas, near the Mexican border is being investigated as possible arson, authorities said.

It is the third church in the city's Catholic diocese to have a fire since early May. All three incidents are under investigation.

In the latest incident, firefighters responding to a blaze at St. Jude Catholic Church on Saturday encountered heavy smoke coming from the main sanctuary of the church, and upon further investigation, found a broken window near the chapel’s altar.

A team from the Dallas division of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) is helping the local fire department with the investigation, along with the El Paso Police Department, the FBI and the Immigration and Customs Enforcement federal agency, according to ATF Dallas’ Twitter account.

Prior to Saint Jude, two other churches in the El Paso Catholic Diocese had fires in May, diocese spokesman Fernando Ceniceros told NBC News.

“Even though we have safety protocols in place,” Ceniceros said, “three of our parishes have been attacked and that causes concerns.”

In both cases in May, at St. Matthew’s Church and the St. Patrick’s Cathedral, incendiary devices hit the properties outside, he said.

In contrast, Saint Jude is "the first time that the fire penetrated the actual infrastructure of the building,” Ceniceros said.

A fire battalion chief at the scene told NBC affiliate KTSM that all church fires are treated as possible criminal investigations.

Ceniceros urged that anyone who may have information about any of the incidents contact the appropriate authorities.

“We’re praying for everyone, including the individuals involved,” said Ceniceros. “Because we are always open to forgiveness.”