Two strong earthquakes levelled villages and damaged homes in northwestern Iran on Saturday, killing at least 180 people and injuring more than 1,350 others, state TV reported. Thousands of people spent the night outdoors as aftershocks rattled the area.

The U.S. Geological Survey reported that Saturday's first quake at 4:53 p.m. had a magnitude of 6.4 and struck 60 kilometres northeast of Tabriz at a depth of 9.9 kilometres. Its epicentre was a region between the towns of Ahar and Haris, about 500 kilometres northwest of the capital Tehran, according to Khalil Saei, local Crisis Committee chief.

The second quake with a magnitude of 6.3 struck 11 minutes later, the USGS reported. Its epicentre was 48 kilometres northeast of Tabriz at a depth of 9.8 kilometres.

The quakes hit the towns of Ahar, Haris and Varzaqan in East Azerbaijan province, the TV report said. At least six villages were totally levelled, while 60 others sustained damage ranging from 50 to 80 per cent.

At least 10 aftershocks jolted the same area and were felt in a wide region near the Caspian Sea, causing panic among the population.

Saei urged people in the quake region to stay outdoors and spend the night at parks and open spaces in anticipation of more aftershocks. Authorities feared the death toll could rise as rescuers were still trying to reach people trapped under rubble and had not yet reached some more remote villages.

Iran is located on seismic fault lines and is prone to earthquakes. It experiences at least one earthquake every day on average, although the vast majority are so small they go unnoticed.

In 2003, about 26,000 people were killed by a magnitude 6.6 quake that flattened the historic southeastern city of Bam.