At least three students and one teacher have been killed and several others injured following a shooting at a school in southern Turkey, the local governor has said.

The incident happened at Ayser Calik Secondary School in the Kahramanmaras area, local media reports.

The attacker was also killed during the incident, Kahramanmaras Governor Mukerren Unluer said.

It comes a day after 16 people were injured after an ex-student opened fire at another high school, also in the south of the country, before killing himself.

At least 20 people were injured in the attack, Unluer said, adding that some were in a critical condition.

The motive of Wednesday's attack is not yet known and an investigation has been launched.

Turkish media reported that the attacker entered two classrooms and had five guns and seven magazines with him, which Unluer alleged belonged to his ex-police officer father.

"The sound of gunfire was very intense," a reporter for Turkish broadcaster NTV said, adding that there was "panic in front of the school".

Footage from the scene showed crowds of people, some filming on their mobile phones, and ambulances driving away. (BBC)