Twelve people were killed and three others injured in a traffic accident when a church bus and a pickup truck collided in Texas state of US on Wednesday.

The accident took place outside a state park, about 120 km west of San Antonio, a city in central Texas, media quoted an official from Department of Public Safety as saying.

The church bus, which was carrying 14 passengers from First Baptist Church of New Braunfels, was travelling south on Highway 83 in central Texas when it had a head-on collision with a pickup truck, in which there was only a driver.

The officials said the injured were rushed to a hospital but it was not clear if the driver of the pickup truck was among the dead.

Texas Governor Greg Abbot said he and his wife, Cecilia, extended their "deepest condolences to the victims and the families of those involved in today's tragic event."

He said they were "saddened by the loss of life and our hearts go out to all those affected."   

The Texas Department of Public Safety has begun its investigation into the crash. The exact cause of the accident is not clear yet.