Hungary closed the Danube to river traffic on Friday, February 10 because of thick ice, bringing shipping to a near standstill on Europe's busiest waterway, as the continent's cold snap death toll reached past 540, AFP reported.

"Shipping was ordered stopped overnight Thursday to Friday because of conditions created by icing along the Hungarian part of the river," Istvan Lang, who heads the national technical supervisory body OMIT said.

"All ships still underway must immediately head for the closest harbour," Lang, quoted by MTI news agency, said.

Other countries along the Danube, including Austria, Croatia, Serbia, and Bulgaria, had already suspended river traffic because of the freeze.

The 2,860-kilometre (1,780-mile) river, which flows through 10 countries and is vital for transport, power, irrigation, industry and fishing, was nearly wholly blocked from Austria to its mouth on the Black Sea.

In Hungary, 60 to 70 percent of the river was frozen, with only ice-breakers remaining in action, especially in the south of the country, officials said.

The cold snap, which started two weeks ago, is expected to continue until mid-February, forecasters said.