A volcano blasting steam and ash into the atmosphere has formed new craters spewing lava in the south of Iceland. The volcano under the Eyjafjallajokull glacier began erupting on March 20, forcing hundreds of people to leave the area and leading authorities to divert flights. A new fissure - about 300 metres long opened up on Wednesday. Geologists believe this could mean activity is moving further north, towards the nature reserve of Thorsmork, a popular tourist site. A spokesman for the Civil Defence in Reykjavik told the newspaper, Morgonbladid, the fissure was still expanding and that they wanted people to move away from the area as a precaution. Police estimate that about 25,000 people have visited the site in recent days. Iceland lies on a volcanic hotspot in the Mid-Atlantic Ridge and is prone to eruptions, although most occur in sparsely populated areas and pose little danger to life or property. The last eruption took place in 2004.