The 7.3 magnitude quake struck northeastern Iraq and western Iran, according to an initial assessment reported by Iranian state television.
According to the U.S. Geological Survey, the quake struck 15.5 miles beneath the surface about 20 miles from Halabjah, Iraq.
Local media reported that eight villages in Iran had been damaged by the quake and rescue teams had been sent to those areas.
Faramarz Akbari, governor of the Iranian city of Ghasr-e Shirin, said that six people had died and scores more injured, according to the state-run IRNA news agency.
It wasn't immediately clear if there were casualties or how much damage the temblor caused.
Health officials said most of the wounded were in Darbandikhan, 75 kilometres (47 miles) east of the major city of Sulaimaniyah in the semi-autonomous Kurdistan region.
Many residents in the Iraqi capital of Baghdad rushed out of houses and tall buildings in panic.
The quake struck in northeast Iraq - near the border with Iran.
A magnitude 7.2 natural disaster shook Iraq on Sunday, authorities said, without causing any casualties or major damage in the country or in neighbouring Iran and Turkey where it was also felt.
"I felt like I was on a boat, I thought it was vertigo".
Iraq's meteorology centre advised people to stay away from buildings and not to use elevators, in case of aftershocks.