This is the moment a tourist flies his drone across a Russian lake to film a group of people watching the swans arriving for winter and the ice suddenly gives way, sending around a dozen people plummeting into the icy water.

The incident was filmed at a swan sanctuary at Lake Svetly in the southern Russian region of Altai Krai, bordering with Kazakhstan.

Visitors need to buy a ticket to see the swans wintering on the lake. However, a group of tourists decided to go around the entrance and avoid paying, according to the news site Vesti.

While standing at the edge of the lake, the thin ice gave way and around a dozen people fell into the water.

Eyewitnesses said none of the tourists were injured in the incident, as the water is very shallow at that point, adding that visitors cross a bridge if they pay the RUB-50 (GBP-0.50) entrance fee, but nothing prevented anyone from entering the sanctuary by walking along the shore.

Following the incident, the local authorities strengthened security in the area and the number of visitors is being closely monitored during this busy period.

Rules are also read out to visitors via a PA system and possible alternative routes to the area have now been cordoned off.

Lake Svetloye does not freeze in winter and it is a popular spot for swans to spend the cold months.

Thin ice often forms around the shore, making it difficult to walk across. However, the Ministry of Natural Resources and the Environment has provided special walkways and viewpoints where paying visitors can safely enjoy the spectacle.