According to Tasnim news agency quoting the Iranian Seismological Center of Tehran University, the epicenter was determined at Sefid Sang, a city in Qalandarabad District in the Khorasan Razavi Province.
There were no immediate reports of casualties and the extent of the damages inflicted on the quake-hit area.
The epicenter, with a depth of 10 km, was determined to be at 35.83 degrees of latitude and 60.26 degrees of longitude.
Some breakdowns have been reported in communication systems in Mashhad following the earthquake.
Meantime, five aftershocks, including a 4.7-magnitute quake have happened in Mashhad.
Rescue teams from the Iranian Red Crescent Society (IRCS) have also been deployed to the quake hit areas.
Head of Khorasan Razavi’s Red Crescent Society Mojtaba Ahmadi said the teams were sent to Sefid Sang, Sarakhs, Torbat Jam, Fariman and also holy city of Mashhad.