The helicopter, belonging to Iran Helicopter Support and Renewal Company, crashed in Lake Chitgar at 11:40 a.m. local time on Tuesday, according to a statement by the company.
All of the 8 people on board the chopper were rescued from the lake after the crash and have been admitted to hospital, it added.
The cause of the incident is under investigation, the statement noted.
The artificial lake of Chitgar was made next to a large forest park of the same name a few years ago.