The spokesman said that there were two people aboard the plane. Their condition remains unknown.
According to the spokesman, the helicopter left the Oek base 50 km north of Irkutsk at about 11 a.m. on a mission for the air forest police.
At 3 p.m., an inspector from the Baikal nature reserve saw the helicopter fall near Lake Baikal. He headed for what he thought was the crash site. However, he only discovered the helicopter's screw on the lake's bank. The ministry suggested that the plane could have crashed into the water.
Two hours later, a motorboat carrying an eight-person rescue team set off to search for the wreck and possible survivors.
The search, however, will only begin Thursday morning since the crew will not reach the site before nightfall.
