"In principle, the airport has ceased operations" as of 7:30 pm (1830 GMT) because "it's a real ice rink", according to a spokesperson.

Around 30 flights were scheduled to depart from that time, while around 70 were scheduled to land.

No departures have been possible since Thursday morning, with some landings also cancelled.

By late afternoon, "several dozen" flights had already been cancelled, another spokesperson told AFP, adding that she could not provide precise figures due to the quickly evolving situation.

A red ice warning issued by the German Weather Service (DWD) in the early evening applied to much of eastern Germany, from southwestern Berlin all the way to the Baltic Sea.

The regional cold snap has caused several accidents and disruptions, including a series of crashes on a Potsdam highway that injured around 20 people in the afternoon.

In Berlin, the ice covering the capital has fuelled a dispute over the need to use salt -- an environmentally harmful substance -- on roads to prevent accidents.

January in Germany was significantly colder than the national average for the past three decades, according to the DWD.