A snowstorm in Istanbul grounded planes, halted traffic and forced the closure of the Bosphorus Strait shipping channel today.

Turkish Airlines, Europe's fourth-largest carrier, said it was forced to cancel more than 300 flights scheduled for today and tomorrow. Today's flight to Malta was among them.

Ataturk Airport, Istanbul's main airport and the fourth-busiest in Europe, closed briefly in the morning because of the adverse weather, but reopened by early afternoon.

Some commuters in the city of 15 million had to walk to work after as much as 60 cm (24 inches) of snow fell in two days in parts of Istanbul.

The storm also stranded members of the Besiktas football team for hours. The Istanbul side is scheduled to play Liverpool in England later today.

The club said on its website the players had finally departed from Sabiha Gokcen Airport on the Asian side of the city instead of the planned morning flight from Ataturk.

Discount carrier Pegasus also called off some flights at its hub at Sabiha Gokcen.

The Bosphorus, which divides Istanbul into Asian and European districts, was shut in both directions.

At least 13 tankers were waiting to enter the strait at both ends and were now scheduled to make the voyage tomorrow, shipping agent GAC said. The Dardanelles at the opposite end of the Sea of Marmara remained opened, it said.

Maritime authorities regularly shut the Bosphorus, the only navigable waterway for Russian commodities, due to reduced visibility in winter months, which raises cargo costs. Some 10,000 tankers carry 150 million tonnes of petroleum products through the narrow, winding strait each year.

Icy roads had led to more than 800 traffic accidents since late on Tuesday, the mayor's office said.