Few details were immediately available. A spokesman for the police department in Santa Fe, about 30 miles (48 km) southeast of Houston, said officers were “still establishing the scene.”
It was not clear whether anyone was hurt.
The Santa Fe School District said in a statement that it initiated a lockdown after an active shooter incident at the high school. It said it would send out more information as soon as it was available.
Houston-area media reported that the Harris County and Galveston County sheriff’s offices were also sending deputies to the scene, and that a Life Flight was called to the school.