An earthquake of magnitude 5.2 struck a town near the Iranian capital Tehran on Wednesday night, state media reported, but there were no initial reports of casualties or significant damage.
Authorities said they were gathering information and asked residents to remain calm but be prepared for possible aftershocks.
The epicenter was at Meshkin Dasht in Alborz Province, 50 km (30 miles) west of Tehran, Tasnim news agency quoted Morteza Salimi, the head of Relief and Rescue Organization of Iran's Red Crescent, as saying.
The quake was also felt in the cities of Karaj, Qom, Qazvin and Arak, according to state TV.
"There have been no reports of casualties or damage," Behnam Saeedi, a spokesman for Iran's National Disaster Management Organization, was quoted as saying by the ILNA news agency.
In parts of Tehran residents flooded into streets and parks, fearing a stronger aftershock.
Last month, a 7.3-magnitude earthquake hit villages and towns in Iran's western Kermanshah province along the mountainous border with Iraq, killing 620 people and injuring thousands of others.
