A police officer was killed and three were wounded when a psychically unstable man opened fire in Bulgaria's town of Lyaskovets, near Veliko Tarnovo. 

According to the local media Petko Petkov, 53, is mentally ill, unemployed and hasn't left his home across the school in downtown Lyaskovets since 2010. He has been complaining from the children playing in the schoolyard and more than once has threatened to shoot at them.

According to viewers of Bulgaria's public TV channel BNT the police has besieged Petkov's house around 5.30 AM today and has been calling on him to surrender. He opened fire in response.

The siege continues.

The school principal has repeatedly informed the police about the threatening letters sent by Petkov and has warned the children to avoid playing in the yard and steer clear of Petkov's house.

Teachers at the school say the latest letter was from yesterday, while children claim he had threatened them in person.

“This man is my neighbour and he's extremely dangerous”, said a viewer of Bulgaria's Nova TV.