Tehran - At least five people were killed and more than 300 injured as a 5.9-magnitude earthquake hit north-western Iran in the early hours of Friday morning, Iranian media reported.
Reports said at least 400 houses had been damaged.
The quake struck at 2:17 am (22:47 GMT) some 50 kilometres north-east of Hastrud, a city in Iran's north-west towards the borders with Armenia and Azerbaijan, according to the US Geological Survey (USGS).
"Rescue teams and helicopters have been dispatched to the quake-hit areas and hospitals are on full alert to help injured people," Iran's emergency medical services chief Pirhossein Kolivand was quoted as saying by Press TV's English website.
Army units have also been put on standby.