Armed man holding hospital staff hostage in Istanbul

Turkish media says the gunman is believed to be a patient at psychiatric unit of Istanbul's Cerrahpasa hospital

An armed man is said to have held staff of a hospital hostage in Turkey's Istanbul city.

According to media reports, the man is believed to be holding a number of doctors and other staff hostage.

Turkish media said the gunman is believed to be a patient at the psychiatric unit of Istanbul's Cerrahpasa hospital and is threatening to kill himself and others.

Police and rescuers have arrived at the scene while patients and staff have been evacuated from the hospital.

This is a developing story and will be updated accordingly.