Air travel to and from Europe faces further disruptions as most countries on the continent decided to extend flight bans into next week while carriers from other countries continued to cancel their flights to European destinations.

Meanwhile, the volcanic ash cloud from Iceland has spread further south and east towards Greece and Russia, amid fears of further eruptions.

France decided to shut the three airports in the Paris area and others in the north of the country until 8:00 a.m. (0600 GMT) on Monday. Italy also said it would not allow any flights in the north of the country until 0600 GMT Monday, while Belgium, Britain, Ireland and Germany shut their airspace until 1200 GMT Sunday.

Other European nations also moved to extend their flight bans, including Austria to 0000 GMT Sunday and Belgium to 1200 GMT.

Poland said it was shutting its airspace "until further notice", stopping world leaders from flying to the southern city of Krakow for Sunday's funeral of late president Lech Kaczynski and his wife Maria, who were among 96 killed in a plane crash in Russia on April 10.

On Saturday, a total of 17,000 flights in European airspace were canceled, with only 5,000 in operation, out of a normal total of 22,000 flights on the continent, according to Eurocontrol, which coordinates air traffic control in 38 nations.

Countries in other parts of the world have also canceled their flights to Europe for at least three days. In the United States, out of 337 scheduled flights to and from Europe, 282 flights were canceled on Saturday, accounting for 84 percent of the total, according to the Air Transport Association of America. It is expected that many of the U.S. flights would remain canceled through Sunday.

The International Civil Aviation Organization warned Saturday that the air traffic disruptions caused by the ash cloud from the Icelandic volcanic eruption exceeded the disruptions by the September 11, 2001 attacks on New York and Washington.

While the disruptions have caused great inconvenience to passengers, authorities have warned of serious damage to the travel industry. The International Air Transport Association, which represents 230 airlines operating 93 percent of global trade traffic, estimated the cost of the airspace shutdown for the industry amounts to about 200 million U.S. dollars each day.

In Denmark, some travel companies have pledged to allow customers to cancel their trips and reclaim the costs. The Scandinavian airline SAS has decided that they will ask over 2,500 Norwegian employees to have unpaid holidays from next Monday if the situation does not improve. Some Danish hotels have greatly increased their prices.

The current spate of volcanic eruptions from under Iceland's Eyjafjallajokull glacier started Wednesday. Since then, thick clouds of black and brown ash have been spreading south and east to other parts of Europe.

The ash cloud has now spread east to Russia and is heading south close to Greece. Winds will continue to blow in the same direction for at least two days and could go on until the middle of next week, spreading more ash throughout the European continent, scientists have warned.

Officials have justified the widespread airport closures by saying that airplane engines could become clogged up and stop working if they try to fly through the ash.

In the past 20 years, there have been 80 recorded encounters between aircraft and volcanic clouds, causing the near-loss of two Boeing 747s with almost 500 people on board and damage to 20 other planes, experts say.

To assess the impact of volcanic ash on aircraft and find an earliest date to resume flights, the European Organization for the Safety of Air Navigation made a few test flights Saturday.

One KLM Royal Dutch Airlines Boeing jet took off from Germany's Dusseldorf airport on Saturday night and landed safely at Amsterdam's Schiphol airport. Other test flights had taken place in France and Belgium during daytime on Saturday.

The test flights, meant to establish whether air quality in the atmosphere met the requirements for safe flight, were performed at lower altitude than usual, and no passengers were on board.

KLM CEO Peter Hartman said that during the flight of his company, no problems were encountered.

"At first glance there is no reason to suspect that anything is amiss. We observed no irregularities either during the flight or during the initial inspection on the ground," he said. He expected final results of the technical inspection to come out on Sunday morning.

"We hope to receive permission as soon as possible after that to start up our operation and to transport our passengers to their destinations," he said.