Friday's quake hit 57 kilometers (35 miles) from the city of Hashtrud in East Azerbaijan Province, at 2.17 a.m. local time (5.47 p.m. ET), according to the US Geological Survey.
Most of the injuries were caused by crowd stampedes, state-run TV reports.
The area is some 400 kilometers (250 miles) northwest of the capital, Tehran. "Unfortunately six people were killed and 345 injured", Iran's emergency medical services chief, Pirhossein Kolivand, told state TV. There were no immediate video or images broadcast from the area.More news: 1st batch of Samsung's Galaxy Fold sells out online on 1st day
Rescuers have been dispatched to the region, officials said, with 30 homes reportedly destroyed at the epicenter of the quake. Geological Survey (USGS) listed the quake's magnitude at 5.8 with a depth of 10 kilometers.
Tabriz has been the site of many deadly earthquakes throughout history.
A night-time quake in northwestern Iran on Friday killed five people and injured 120, according to early reports on state television.More news: Man Falls to His Death in Lava Tube Hiding in His Yard
Iran is prone to earthquakes as it sits on major fault lines and experiences an average of one temblor a day.
The deadliest this century occurred in 2003 when a magnitude 6.6 natural disaster struck the southeastern city of Bam, killing some 26,000 people. Join now and for as little as $6 a month you can both help ensure our ongoing investment in quality journalism, and enjoy special status and benefits as a Times of Israel Community member.More news: Facing arrest, Cambodia's Sam Rainsy says he will return Saturday