Rescue efforts are being stepped up to help those affected by the magnitude-7.5 earthquake which hit remote areas of Afghanistan and Pakistan on Monday.

Rescue teams have been sent to remote mountainous areas where the effects of the quake are still unclear.

The quake's focus was deep, reducing its impact. Victims included 12 Afghan schoolgirls killed in a stampede as they tried to leave their classes.

"They fell under the feet of other students," a disaster official in the province of Takhar told Reuters.

Reports said many people across the region, afraid of a new quake, spent the night sleeping outside in temperatures close to freezing.

Afghan President Ashraf Ghani, in a televised address, urged those living in affected areas to help the rescue effort.

Afghan chief executive Abdullah Abdullah said about 76 people had been killed and 268 injured. The numbers were expected to rise, he warned.

The governor of Badakhshan province, Shah Waliullah Adeeb, said survey teams were heading into more remote areas on Tuesday but rocks and landslides had blocked roads and helicopters were needed.

He said food and other essential aid were ready to go but "getting there is not easy".

The Taliban, which controls parts of the province, called on aid agencies "not to hold back" relief supplies and ordered its fighters to help the victims.

Most fatalities reported so far are in northern Pakistan, with at least 230 people killed and 1,629 injured.

In Khyber Pakhtunkhwa province alone, authorities said at least 184 people had died, and more than 1,400 were injured. At least another 30 died in the north-western tribal areas.

The Pakistan Red Crescent tweeted that its disaster response team had been dispatched to the affected areas.

India, Iran and US forces in Afghanistan have all offered help, but so far the local authorities have not requested assistance.

After the quake, Facebook launched its "safety check" feature allowing people in affected areas to tell their families they are safe. Google also launched its "person finder" service.

The US Geological Survey (USGS) reported that the earthquake was centred in the mountainous Hindu Kush region, 76km (45 miles) south of Faizabad, in Badakhshan province.

It was deep - over 200km (125 miles) below the surface - which meant the shaking at ground level was less than for a shallow earthquake.

The USGS said a series of aftershocks - all measuring 4.0 or higher - had struck west of the original quake.

Residents of Kabul and the Indian capital Delhi were shaken by the earthquake, which sent frightened people rushing into the streets.

Buildings in the Tajik capital Dushanbe were also damaged by the tremors.

The region has a history of powerful earthquakes caused by the northward collision of India with Eurasia. The two plates are moving towards each other at a rate of 4-5cm per year.

In 2005, a magnitude-7.6 quake in Pakistan-administered Kashmir left more than 75,000 people dead.

In April this year, Nepal suffered its worst earthquake on record, with 9,000 people killed and about 900,000 homes damaged or destroyed.

Source: BBC