(FOX NEWS) At least 20 people are feared dead in Texas after a gunman opened fire at a church outside San Antonio on Sunday, Fox News has learned.

The mass shooting was reported at First Baptist Church of Sutherland Springs, which is about 30 miles southeast of San Antonio. The gunman has been fatally shot by police, Fox News has confirmed.

Wilson County Commissioner Larry Wiley told Fox News that an emergency responder said between 20 and 24 people are dead, and around 20 were wounded when a man walked into the church about 11:30 a.m. on Sunday and opened fire at the crowd of people.

Emergency personnel respond to a fatal shooting at a Baptist church in Sutherland Springs, Texas, Sunday, Nov. 5, 2017. (KSAT via AP)

Emergency personnel respond to a fatal shooting at a Baptist church in Sutherland Springs, Texas, Sunday, Nov. 5, 2017.  (KSAT via AP)

"It is horrible," Wiley said of the massacre, the motive of which is unknown. "It appears someone walked in and started shooting."

Wiley added he heard children were among those killed.

"We have accepted a multiple number of patients from the shooting," Megan Posey, a spokeswoman for Connally Memorial Medical Center in Floresville, 15 miles from church, said. She said she did not have a specific number. She said doctors were assessing the patients.

Helicopters and emergency personnel were seen arriving at the scene. The FBI is also on scene.

The gunman, according to Wiley, was killed roughly five miles away in Guadalupe County after being cornered by deputies.

President Trump, who's currently traveling in Asia, tweeted: "May God be w/ the people of Sutherland Springs, Texas. The FBI & law enforcement are on the scene. I am monitoring the situation from Japan."

TRUMP, POLITICIANS REACT TO TEXAS CHURCH SHOOTING

Texas Governor Greg Abbott said in a statement that "While the details of this horrific act are still under investigation, Cecilia and I want to send our sincerest thoughts and prayers to all those who have been affected by this evil act."

"I want to thank law enforcement for their response and ask that all Texans pray for the Sutherland Springs community during this time of mourning and loss," the statement read.

Sutherland Springs has a population of about 400 residents.

This is a developing story. Check back for updates. Fox News' Robert Gearty and Jake Gibson contributed to this report.