At least 21 people have been killed and 88 others injured in Iran in accidents related to heavy snowfall and strong winds, state media reported Monday. Iran has suffered from the most serious snow storms in a decade since Saturday - forcing schools and government offices to close, blocking major roads and leading to the cancellation of all domestic and international flights. As much as 55 centimeters of snow has fallen in areas of northern and central Iran, said meteorologist Ali Abedini. Heavy snow also blanketed the capital of Tehran on Sunday, the second time in a week. "At least 21 people have been killed and 88 others injured ... as a result of heavy snow," state-run radio reported. "Some died of the severe cold, some were buried under avalanches and others died after their cars overturned on snow-covered roads."