The epicentre of yesterday's quake that lasted 10-15 seconds was in the border region of Afghanistan and Tajikistan in the Hindu Kush mountains at a depth of 236 kilometres.
Five people died in Khyber-Pakhtuknkhwa province, while one died in Diamer area of Gilgit-Baltistan region, officials said, adding 28 people were injured in Peshawar.
The quake was felt also felt in Pakistan-occupied Kashmir (PoK).
In capital city Islamabad, terrified residents fled their homes in panic and were seen praying in the public.
However, the United States Geological Survey (USGS) measured the earthquake at 6.6 magnitude, putting the epicentre at a depth of 210 kilometres near Ashkasham in Afghanistan, close to Chitral near the Pak-Afghan border.
The quake was the strongest since a powerful 7.5-magnitude quake rocked parts of Pakistan and Afghanistan last October, killing almost 400 people and destroying thousands of home in the rugged mountainous border regions of the two countries.