Officials said nine people, including the governor of Qazvin province Massoud Emami, also died when their helicopter crashed during a a flight to survey the damage in scattered villages in the Elburz mountain range.

The chopper was believed to have hit a mountain in bad weather near the town of Maroukin, a provincial official told the state news agency IRNA. Also on the flight were two members of the governor's cabinet, the province's police chief, a military commander and a journalist.

Three days of mourning have been called in Qazvin province, where around four people were killed in Friday's quake.

The other deaths occurred in the neighbouring province of Mazandaran, and most died from major rockfalls along the hazardous mountain road linking Tehran with the Caspian Sea city of Chalus.

Tehran University's Geophysics Institute said the area had been hit by 157 aftershocks since Friday. The tremors ranged from 1.5 to 5.5 on the Richter scale, and were centered on Baladeh, around 70 kilometers (45 miles) due north of Terhan.

Iran lies on some of the world's most active seismic fault lines, and quakes are common. During the 20th century, around 20 big quakes hit Iran, leaving more than 140,000 dead.

In December last year, some 26,000 people died in a massive quake that levelled the historic southeastern city of Bam.

TERRA.WIRE