Air traffic between Greenland and Denmark has been temporarily halted after ash spewing from Iceland's Grimsvotn volcano reached the airspace over eastern Greenland, civil aviation authorities?in Copenhagen?said Monday.

Smoke rises from the Grimsvotn volcano, under the Vatnajokull glacier in southeast Iceland May 21, 2011. Ash from a massive plume of smoke from an eruption of Iceland's most active volcano could spread south to parts of Europe next week, but experts on Sunday still hoped the impact on air travel would be limited. The eruption at Grimsvotn has so far hit only Iceland, which closed its international airspace. A thick cloud of ash blocked out the daylight at towns and villages at the foot of the glacier where the volcano lies and covered cars and buildings.? [Agencies]

According to Naviair, which manages Danish air traffic services, a small portion of Greenland's airspace remains shut as the ash-cloud continues to spread inwards from its eastern coast.

As a result, commercial carrier Air Greenland announced that it has suspended flights between Kangerlussuaq, in western Greenland, and the Danish capital Copenhagen.

The company justified the suspension on safety grounds in a press release Monday, saying it was not operationally possible to fly around, or over, the ash-cloud which reaches up to 15 kilometers high into the atmosphere. It does not have an alternative airport in the North Atlantic region to fly from either, it added.

Meanwhile, Danish meteorologists said the ash could reach the skies over Denmark late on Tuesday.

"It appears the ash-cloud arrives in Denmark on Tuesday evening. We cannot say much about its concentration yet," said Jens Havskov Soerensen, expert in atmospheric dispersion at the Danish Meteorological Institute, in a statement carried on the Institute's website.

The Institute predicts that a part of the ash-cloud will drift across the United Kingdom before hitting Denmark and a small area immediately south and east of the country, as well as extending over southern Norway and Sweden, late on Tuesday. It is expected to linger over Danish airspace Wednesday, but disperse after that.

A digital map showing the expected movement of the ash between early Monday and Tuesday night was released on the Institute's website.

The Grimsvotn volcano, which lies under the Vatnajokull glacier in south-eastern Iceland, began erupting Saturday, and is undergoing its largest eruption in almost a century.

Soerensen explained that the atmospheric currents transporting the ash can be predicted with reasonable certainty from between 24 and 48 hours in advance. However, the quantity and size of the ash- particles can impact their spread and concentration.

Following the eruption, Iceland's air traffic authorities closed the country's main airport at Keflavik, canceled all domestic flights, and put a no-fly zone in place around the volcano.

The ban has affected direct flights between Denmark and Iceland, and some trans-Atlantic flights that normally stop in Iceland en route from Denmark to North America.

In April last year, ash spewing from a major eruption on Iceland's Eyjafjallajokull volcano closed much of Europe's airspace for almost one week.