Details are still unclear.
The shooter was killed after a brief chase north into neighboring Guadalupe County, according to Guadalupe County Sheriff's Office spokesman Robert Murphy.
President Donald Trump tweeted from Japan that he is monitoring the situation.
He said he is on his way to Sutherland Springs to meet with families, local, state and federal officials.
Police and paramedics responded to First Baptist Church of Sutherland Springs, TX around late morning Sunday on word of an active shooter at the premises.
Sutherland Springs is a town with a population of roughly 362, and is located 35 miles east of San Antonio. "The FBI & law enforcement are on the scene", he said on Twitter.
In a statement, Governor Abbott said: "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".
A woman who lives about 10 minutes away from Sutherland Springs in Floresville and was monitoring the chaos on a police scanner and in Facebook community groups, said that everyone knows everyone in the sparsely populated county.
It appears that there are 27 confirmed deaths from the bad attack and dozens more injured.
Emergency officials are on scene and updated reports are expected.
Two Airlife helicopters arrived at the scene while a sheriff's department dispatcher said everyone is at the scene and unavailable to comment.
Today's massacre is already the worst church shooting in U.S. history, surpassing the nine killed at a Baptist Church in SC in 2015.