The quake at a depth of 210 kilometres (130 miles) occurred at 2:58 pm (1028 GMT), 282 km northeast of the capital Kabul.
The quake was felt for a few seconds in Kabul and in Pakistan's capital Islamabad, where some residents evacuated apartment blocks after tremors shook ceiling fans and furniture.
Last October a 7.5-magnitude quake ripped across Pakistan and Afghanistan, killing almost 400 people and flattening buildings in rugged terrain that impeded relief efforts.