Four people were killed when a helicopter crashed into a vegetable market on Tuesday in Iran’s central province of Isfahan, local authorities said.

In a statement, Isfahan province said the helicopter went down in the city of Dorji “due to a technical malfunction,” according to Iranian media reports.

The statement said the pilot and co-pilot, along with two people at the market, were killed in the incident.

Authorities have opened an investigation to determine the exact cause of the crash, and firefighters brought a blaze triggered by the crash under control.