A man clears debris after his house partially collapsed following an earthquake, in Srinagar, India April 10, 2016. REUTERS/Danish Ismail

By Paul Tait

KABUL (Reuters) - An earthquake with a magnitude of 6.6 struck South Asia on Sunday, shaking buildings in Pakistan, Afghanistan and India, witnesses and the U.S. Geological Survey (USGS) said, and injuring several people in at least one Pakistani city.

The USGS said the quake was centred about 40 km (25 miles) west of Ashkasham in remote northeastern Afghanistan, close to the border with Tajikistan and just across a narrow finger of land from Pakistan's northwestern Chitral province. It was measured at a depth of 210 km (130 miles).

Residents left their homes in Kabul and Islamabad when the quake struck, with buildings swaying for more than a minute in both capitals. Similar reports were received from across northern and central Pakistan.

In Pakistan's northwestern frontier city of Peshawar, Khalid Khan, emergency director at the city's main Lady Reading Hospital, said three people were treated for "multiple injuries". Media pictures showed two children who appeared to have been injured in the quake.

People in Lahore in Pakistan's east, 630 km (390 miles) from the epicentre, also reported they had felt the tremors.

A Reuters witness in Chitral said the tremor was strong but there was no major damage visible.

A 7.5-magnitude quake struck the area on Oct. 26 last year, killing more than 300 people and destroying thousands of homes.

In Kabul, Omar Mohammadi, a spokesman for the Afghanistan National Disaster Management Authority, said officials were collecting information but no reports of casualties or damage had been received so far.

Tremors were also felt in the Indian capital and in Kashmir, witnesses said, with some people working in high-rise buildings in the Indian capital rushing into the streets.

The Delhi underground system was also halted briefly, commuters told the NDTV channel.

The Hindu Kush area bordering Pakistan and Afghanistan is a seismically active area, with quakes often felt across the region. Just over a decade ago, a 7.6-magnitude quake in another part of northern Pakistan killed about 75,000 people.

(Additional reporting by Hamid Shalizi in KABUL, Asad Hashim, Kay Johnson and Jibran Ahmed in ISLAMABAD, Gul Hammad Farooqi in CHITRAL, and Sanjeev Miglani in NEW DELHI, Editing by Ros Russell)