Two people were killed in a shooting at a church near Fort Worth, Texas, on Sunday morning and a third person has been taken to a hospital in critical condition, officials said.

MedStar Mobile Healthcare spokeswoman Macara Trusty told the Associated Press that two people were fatally shot at the West Freeway Church of Christ in White Settlement. A third person in critical condition is being treated at a hospital and all of the victims are male, she said. MedStar is an ambulance service.

Authorities have not released any details about what led to the shooting.

An elder at the church told the New York Times that one of those killed was a security guard who responded to the shooter, calling him a dear friend.

"He was trying to do what he needed to do to protect the rest of us," said the elder, Mike Tinius.

"It's extremely upsetting to see anyone committing violence," he added.

Tinius said he didn't know the gunman and that the shooting appeared to be random.