"We had to reroute transatlantic flights because of the volcanic plume. We have a several hundred kilometre-wide danger zone between Iceland and northern Norway," Bergthor Bergthorsson, an official at the Icelandic Aviation Authority told AFP.

The subglacial eruption broke out beneath the Grimsvotn glacial lake in the western part of the Vatnajokull glacier in central Iceland at 9:50 p.m.on Monday and was preceded by a series of earthquakes, according to the Icelandic Meteorologic Institute (IMI).

So far, the smoke-spewing volcano, which is located in a sparsely populated part of the island, has not caused any damage, though police did temporarily shut down a large national highway.

The blast, which took place in the same area as a massive eruption of 1998, is the 13th subglacial eruption in the area since 1902, according to Icelandic geologists.

Monday's eruption may have been triggered by the recent draining of the Grimsvotn lake, which unleashed a glacier flood in the area, IMI seismologist Kristin Vogfjod told AFP.

"We have been following the area closely for two weeks and were quite sure that there would be an eruption," she said.

"Friday we let aviation authorities know that (an eruption) should be expected. Monday morning there were continuous earthquakes of up to 3.0 on the Richter scale, and then it was just a question of time," she added.

Air traffic controllers have had to reroute all flights over Iceland, including 10 transatlantic flights.

The wind has so far been blowing north and northeast, but if it starts blowing in a southern or western direction, at least 50 flights a day could be affected.

"I don't even want to think about that," Bergthor Bergthorsson of the Icelandic Aviation Authority in the Reykjavik flight tower told AFP.

The eruption could be seen from as far away as the town of Egilsstadir, some 130 kilometers to the northeast of the volcano, which belched smoke and ashes about 14 kilometers above the glacier in the early hours of Tuesday.

The plume still stood nine kilometers high at noon (1200 GMT) on Tuesday, scientists said.

"It is very imposing and beautiful" said Bjorn Malmquist, a local journalist in Egilsstadir.

"We had magnificent footage" agreed Logi Bergmann Eidsson, deputy news chief at Icelandic state television station RUV, which aired an extra news bulletin at noon on Tuesday dedicated to the eruption.

Not everyone thought the view of the eruption was much to write home about.

"I think it is just a small, dirty and ugly sky. It is just some bureaucratic hysteria to cancel flights. No ash has been detected here," Benedikt Vilhjalmsson, a radio operator at Egilsstadir airport, said.

Scientists believe the eruption is going to follow similar trends as previous eruptions, meaning that it could last up to two weeks.

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