(CNN) -- Hundreds of people were evacuated Sunday amid flood concerns after a long-dormant volcano erupted beneath a glacier in south Iceland.

It was the first time since 1821 that the volcano under the Eyjafjallajokull glacier has erupted.

More than 600 people were evacuated as scientists monitored a fissure in the volcano from which lava was erupting. The fissure measured about 1,640 to 3,281 feet (500 to 1,000 meters).

Despite the remote location of the eruption, if the fissure "develops further towards the glacier, the melting floodwater ... will create dangerous floods in a populated area in south Iceland," said Gudrun Johannesdottir, a project manager for Iceland's Joint Rescue and Coordination Center.

The country's civil protection agency did not immediately record any injuries or damage.

Eyjafjallajokull is about 100 miles (160 kilometers) east of the capital, Reykjavik.

