An earthquake of magnitude 5.7 has struck in the Hindu Kush region where Pakistan and Afghanistan share a border.

The tremor on Saturday morning was felt in the Afghan capital, Kabul, and in the Pakistani capital, Islamabad.

There were no initial reports of fatalities or damage, but buildings swayed.

The US Geological Survey said on its website that the epicentre of the quake was at a depth of 177km.

"The quake was very strong and lasted for 10 seconds. We are expecting casualties, but at the moment we don't have any reports," Munshi Abdul Majid, the governor of the northern Afghan province of Badakhshan, where the epicentre was located, told Reuters news agency.

A Reuters reporter in northeastern Kunar province said: "All my colleagues ran out of the office."

In Peshawar, the capital of North West Frontier Province, assembly members gathered to elect a new president for the country, temporarily fled the building when the earthquake struck.

More than 70,000 people were killed in Pakistan by an earthquake in October 2005.