Volcanic eruption near Iceland capital Reykjavik. Watch video

Streams of red lava bubbled and flowed out of a fissure in a valley in Geldingadalur, close to Mount Fagradalsfjall on the Reykjanes peninsula in southwestern Iceland. As the lava flow slowed under rain showers, a blue gas plume and a vapour cloud rose from the site, just 40 kilometres (25 miles) from the capital and near a popular tourist destination, the Blue Lagoon geothermal spa.

The eruption occurred on Friday around 2045 GMT, lighting up the night sky with a crimson glow as hundreds of small earthquakes shook the area. The Icelandic Meteorological Office (IMO) said the 'eruptive fissure' measured approximately 500 to 700 metres (1,640 to 2,300 feet). The lava area was less than one square kilometre (0.4 square mile), with small lava fountains. IMO said it was very likely the eruption will last for the next few days.

Access to the area was initially blocked off but later opened to the public, though Iceland's Department of Civil Protection and Emergency Management stressed the several-hour hike from the nearest road was only recommended for those "used to being outdoors in difficult conditions." Gases from a volcanic eruption -- especially sulphur dioxide -- can be elevated in the immediate vicinity, and may pose a danger to health and even be fatal. Gas pollution can also be carried by the wind.

The Krysuvik system has been inactive for the past 900 years, according to the IMO, while the last eruption on the Reykjanes peninsula dates back almost 800 years and lasted about 30 years, from 1210 to 1240. Iceland has 32 volcanic systems currently considered active, the highest number in Europe. The country has had an eruption every five years on average.