A strong earthquake has killed at least 20 people and damaged more than 80 villages north of the Iranian capital Tehran, officials say.
The quake reportedly measured 6.2 and affected a large area, its epicentre in Mazandaran province by the Caspian Sea.
The BBC's Jim Muir in Tehran says the toll looks set to rise as news comes in from remote villages, roads to which have been cut off by falling rocks.
A huge quake killed about 26,000 people last year in Bam, south-eastern Iran.
An interior ministry spokesman said the latest earthquake, which struck at about 1700 local time (1330GMT), did not appear to be as catastrophic.
"We don't have any confirmation about the death toll, but we do know it is not very high and the damage is not very significant," Jahanbaksh Jahangiri told the Reuters news agency.
The damage is spread over a much bigger and less densely populated area than in Bam, our correspondent says.
Blocked by debris
The total number of injured is reported to be in the region of 150.
A senior Iranian official said 16 people were killed and 70 injured on the Tehran-Caspian Sea road, which cuts through rugged mountain gorges.
Efforts are under way to rescue many people said to be trapped in their vehicles by fallen rocks.
Army units are on alert to help with the relief effort.
The governor of the northern province of Qazvin told state TV that roads to several villages had been blocked by debris and the province had put out an appeal for aid.
The quake was felt in the capital, Tehran, where it shook buildings, shattering some windows, and sent people rushing out into the streets in panic.
The state news agency Irna said roads had been ripped apart in the worst-hit areas and there were reports of power cuts.
Iran straddles a seismic fault line, making it particularly prone to earthquakes.
Some 35,000 people died when a quake hit the Caspian province of Gilan in 190.