At least 11 hikers died over the weekend in the mountain range north of Tehran when a series of avalanches were triggered by blizzards and heavy snowfall, Iran’s Red Crescent rescue group said.

The rescue efforts, which began on Friday when the first two deaths were reported, intensified over the weekend as more were reported missing.

State television broadcast footage of the helicopter rescue mission searching for bodies and survivors on the Tochal and Kolakchal peaks; as well as Red Crescent personnel carrying a body on a stretcher along a snowy mountainside.

Ten people had been killed on the mountain and one died in hospital after being rescued, Mehdi Valipour, head of emergency operations at Iran’s Red Crescent, was quoted as saying by state broadcaster IRIB.

Tehran lies at the foot of the Alborz mountain range, a popular weekend attraction for hiking and climbing. According to state TV, the avalanches struck in four different areas.

The Iranian Red Crescent said the rescue efforts were complicated by the bad weather.

On Friday, Iranian media reported that more than 100 people were estimated to be stuck in the avalanche.

Shahin Fathi, the managing director of the Red Crescent, told BBC Persian that as of Saturday, families were still reporting seven people missing.

“We may still have injuries in the Kolakchal area, but there are no exact statistics," said Mr Fathi on Sunday.

The Mountaineering Meteorological channel on Telegram warned people in Tehran not to go to the mountains because of the possibility of an avalanche in Alborz.