A magnitude 6.6 earthquake has been felt across a number of major cities across south-west Asia.

The earthquake struck in Afghanistan, close to its border with Tajikistan, at 10:28 GMT, according to the US Geological Survey (USGS).

There are reports the tremor was felt in Kabul, Islamabad, Lahore and Delhi, forcing residents to leave their homes.

In October 2015, a magnitude-7.5 quake in the same border area killed close to 300 people.

The latest quake, in the sparsely-populated Hindu Kush mountains, struck at a depth of 210km, the USGS reported. It was the same depth as the 2015 quake.

There were no immediate reports of damage or casualties.

The USGS says the earthquake took place in "one of the most seismically hazardous regions on earth".

In Delhi, the metro train system was temporarily halted. The BBC's Sanjoy Majumder said a number of aftershocks were felt in the Indian capital.

Hamza Nadeem, 19, felt the earthquake in his home in Sialkot, eastern Pakistan.

"I felt the ceiling fan rattle, then the whole house felt like it was shaking," he told the BBC. "We all ran outside.

"It lasted for about one and a half minutes - nothing broke, there was no damage but it was a frightening experience. We all just stood there and prayed."

Pakistan's Dawn newspaper reported on Saturday that the region had been shaken by a series of strong quakes centred on Hindu Kush in recent days.