Around 500 flights have been canceled from the approximately 29,000 that would have been expected on Tuesday across Europe due to the eruption of an Icelandic volcano, said Europe's air traffic control organization Eurocontrol.

Passengers sleep at Scotland's Edinburgh Airport on Tuesday after their flight was canceled. Ash from an Icelandic volcano forced the cancellation of dozens of flights to and from Scotland.

Area of high ash concentration were over northern Britain, the Brussels-based organization quoted the Volcanic Ash Advisory Center (VAAC) in London as saying. 

According to the VAAC predictions, there is a "strong possibility" that the ash could may impact parts of Denmark, southern Norway and southwest Sweden by Tuesday, said Eurocontrol.

"This would have some impact on flights," said the organization.

The Grimsvotn volcano, which lies beneath the ice of the uninhabited Vatnajokull glacier in southeast Iceland, began erupting Saturday for the first time since 2004, shooting ash, smoke and steam up to 20 kilometers into the air.

Although the eruption was much stronger than the one at a volcano further south in 2010, experts said they saw little chance of a repeat of last year's six-day closure of airspace.

Volcanologists said the ash cloud's content was heavier and less likely to spread this year, while authorities had a higher tolerance for ash levels.

"At this moment it is very unlikely that it will be anything like this when we had a disruption at the same time last year," Brian Flynn, head of Eurocontrol, said in an interview with Xinhua on Monday, quoting also different wind conditions this year.

Eurocontrol, which set up a crisis unit after bad coordination was blamed for worsening last year's crisis, also said Tuesday the Grimsvotn eruption had been "slightly abating."

Nevertheless, the towering ash cloud had forced visiting U.S. President Barack Obama to leave Ireland for Britain one day ahead of schedule over safety concerns.

Volcano ash contains tiny particles of glass and pulverized rock that can damage engines and airframes.