An earthquake measuring 5.6 on the Richter scale has hit eastern Iran, killing at least eight people and injuring 12 others, Iranian media reports.
Iran's Fars news agency said people ran out of their homes after the tremor struck the district of Zahan, in South Khorasan province, on Wednesday.
Walls and buildings collapsed, and several people were left trapped under the rubble.
"Eight people have been killed in the earthquake area and one person is missing. Unfortunately a number of those injured
have lost their lives in the last few hours," Mehr news agency quoted South Khorasan's crisis management director Mohammad Ali Akhundi as saying.
"Homes have sustained damage and people are out in public places and they need the means to keep themselves warm because of the cold," he said.
Officials said the death toll could rise as rescuers reached the affected areas.
Two villages appeared to have sustained the worst of the damage including the village of Sharaj where five people were
killed, Mehr news agency quoted district governor Farhad Falahati as saying.
"We have what we need to help but landslides especially on the route to Sharaj have stopped the relief supplies from
getting there," he said.
Five villages were "destroyed or damaged" in the earthquake, Mohammad Ali Akhoundi, head of the South Khorasan provincial crisis management service, told state media.
At least 12 aftershocks have been registered since the quake struck at 20:38 local time (17:08 GMT), the Iranian Seismological Centre reported.
Iran is situated on major fault lines and has suffered several devastating earthquakes in recent years, including a 6.6 magnitude quake in 2003 which flattened the southeastern city of Bam and killed more than 25,000 people.
In August, more than 300 people were killed when two earthquakes struck in the northwest.