TEHRAN - An earthquake measuring 5.1 on the Richter scale shook Tehran province early on Friday, killing two and injuring 33.

The earthquake occurred at 00:48 a.m. at a depth of 7 kilometers near the city of Damavand, 56km northeast of Tehran.

The tremor was also felt in the surrounding provinces of Qom, Alborz, Mazandaran, and Zanjan.

Esmaeil Najjar, head of the Crisis Management Organization, said a 60-year-old man in Damavand lost his life due to a brain injury. 

Mansour Darajati, Tehran province’s Crisis Management Department director-general, told Mehr that a 21-year-old woman has also died following a cardiac arrest.

Moreover, 33 people were injured, of whom four have been hospitalized, IRNA reported.

Some residents in Damavand, Gilavand, Boom-e Hen, Rood-e Hen, Pardis, the metropolis of Tehran, and some other nearby cities spent the night outdoors, fearing stronger aftershocks.

Iran sits on top of major tectonic plates and experiences frequent seismic activity. In 2003, a 6.6-magnitude quake in southeastern Iran decimated the ancient mud-brick city of Bam and killed at least 31,000 people.

The metropolis of Tehran also sits on two major fault lines.

Mehdi Zare, a renowned seismologist, says the frequent jolts across Iran are the result of "accumulated seismic energy” in the form of natural consecutive seismic events.