A German mayor is in a critical condition after being stabbed 13 times near her home, according to reports.

Iris Stalzer, 57, a member of the centre-Left Social Democrats party, was found with multiple stab wounds by her adopted son at her flat in Herdecke on Tuesday.

The son, aged 15, was taken away in a forensic suit to preserve evidence, reports said.

Ms Stalzer, who was airlifted to hospital following the attack, is receiving emergency treatment. According to German media, the incident is being investigated as an attempted murder.

She was found wounded at around lunchtime on Tuesday, having reportedly dragged herself back inside her home, where she also lives with her 17-year-old daughter.