AFP - Helicopters ferried food and medicine to iced-in villagers Wednesday as Europe's 12-day-old cold snap tightened its frigid grip on the continent, where more than 400 have died as a result.

Eastern countries such as Poland and Ukraine account for more than half of the death toll, and dozens more have succumbed to the weather's secondary effects, such as asphyxiation due to shoddy heating.

Heavy snows eased in Bosnia but the bitter cold continued, especially in the south and southeast where temperatures dropped to minus 20 degrees Celsius (minus 4 Fahrenheit.)