Reykjavik, Dec 19 (IANS): A volcano has erupted on the Reykjanes Peninsula of south-west Iceland after weeks of intense earthquake activity, the national meteorological office said on Tuesday.

"The eruption is located close to Sundhnukagigar, about 4 km northeast of Grindavik, and it can be seen on nearby web cameras," Xinhua news agency quoted the Icelandic Meteorological Office as saying.

It added that the eruption began at 10.17 p.m. on Monday night following the earthquake swarm that started at around 9 p.m.

The length of the crack in the volcano is about 3.5 km, with the lava flowing at a rate of around 100 to 200 cubic metres per second, the Office noted.

It said that this was many times more than in previous eruptions on the Reykjanes Peninsula in recent years.

A coastguard helicopter has been sent to the area to confirm the exact location and size of the eruption.

The National Police Commissioner of Iceland raised the Civil Protection Service Level from Alert to Emergency in response to the eruption.

The Civil Defense Coordination Centre has been activated.

Authorities have asked the public not to go to the eruption site, and the emergency personnel are assessing the situation.

All roads to the town of Grindavik are closed and traffic is prohibited, including Highway 41, the main road along the north side of the Reykjanes Peninsula which connects the greater Reykjavik area and Keflavik International Airport.

The eruption can be seen from capital Reykjavik, which is about 42 km north-east of Grindavik.

The defensive fortifications that began construction recently will make a significant difference to the handling of volcanic eruption, Prime Minister Katrin Jakobsdottir was quoted by local news outlet RUV as saying.

She said her thoughts were with the local community and she was hoping for the best despite the "significant event".

President Gudni Johannesson said safeguarding lives was the main priority but that every effort would be made to protect structures too.

Since October 24, Icelandic meteorologists have been monitoring a rise in seismic activity on the Reykjanes Peninsula, which may signal an impending volcanic eruption.

As a precautionary measure, authorities completed the evacuation of nearly 4,000 residents from the town of Grindavik on the Reykjanes Peninsula on November 10.

In April 2010, the Eyjafjallajokull volcanic eruption caused the largest closure of European airspace since World War Two, as a result of an extensive ash cloud.

Losses were estimated at between 1.5 billion and 2.5 billion euros.