Footage from around Iceland of the moment the quake hit
A strong earthquake measuring 6.1 has hit southern Iceland, 50km (30 miles) from the capital, Reykjavik.
In the town of Selfoss, near the epicentre, buildings were damaged and up to 20 people needed treatment for minor injuries, reports say.
Residents in the capital felt buildings shake and aftershocks were felt in the south-west of the country.
The US Geological Survey said the earthquake struck at 1546 GMT at a shallow 6.2 miles (10 km).
Pall Einarsson, Professor of Geophysics at the Institute of Earth Sciences in Iceland, told the BBC that the earthquake happened in an area popular with tourists:
"It was close to the town of Selfoss and there is apparently, according to the preliminary news, considerable damage in that town," he said.
"Iceland is sitting on a plate boundary where the North America and Eurasian plates are drifting apart. So it's a country of volcanoes and earthquakes and so earthquakes are common but large earthquakes are relatively rare," he added.
"It was quite a lot of shaking... It was quite a big one," Ivar Ingimarsson, a footballer who plays for Britain's Reading club but who is now in Reykjavik, told the BBC.
Danny Austin, a Briton who has been living in the Icelandic capital for a year, told the BBC the earthquake lasted about eight seconds:
"It was fairly noisy. It sounded like thunder coming from the ground. The whole house was shaking, although we haven't had much damage here," he said.
Audbjorg Olafsdottir, an economist in Reykjavik, told Reuters news agency that "the glass in the windows shook and everybody was just really scared".
"In Selfoss, where it happened, I heard everything is broken and people are standing outside in the street and everybody is terrified," she added.
Iceland's national broadcaster RUV radio reported that the road between Reykjavik and Selfoss had been closed due to damage.
Authorities have advised residents in the area to leave their homes because of the possibility of aftershocks.
Iceland, which has a population of about 300,000, is a geologically unstable volcanic island in the north Atlantic.
A spokesman for Iceland's Institute of Earth Sciences said the country had been expecting further quakes after a series of tremors in the same area in 2000.
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