Rescue efforts in Nepal are intensifying after more than 1,800 people were killed in the country's worst earthquake in more than 80 years.

Many countries and international charities have offered aid to Nepal to deal with the disaster.

Seventeen people have been killed on Mount Everest by avalanches - the mountain's worst-ever disaster.

Officials fear that the death toll could rise as the desperate search for survivors continues.

The 7.8 magnitude quake struck an area of central Nepal between the capital, Kathmandu, and the city of Pokhara on Saturday morning.

The latest home ministry figures say 1,805 people were killed and 4,718 people were injured.

There were also victims in India, Bangladesh, in the Chinese region of Tibet and on Mount Everest, where avalanches were triggered.

Little information has emerged from the epicentre, where extensive damage has been reported, and there are fears the death toll could rise yet further.

It is the worst earthquake to strike Nepal since one in 1934 which killed some 8,500 people.

'Moment of crisis'

"We have launched a massive rescue and rehabilitation action plan and lots needs to be done," Information and Broadcasting Minister Minendra Rijal told Indian television.

"Our country is in a moment of crisis and we will require tremendous support and aid."

World leaders and global charities have offered emergency aid to Nepal, as the government grapples with the scale of the disaster.

Its task is made harder because internet and mobile phone communications are erratic, with many roads closed due to quake damage.

The United States, China, Pakistan and European Union countries are among those who have pledged aid.

The US Embassy in Nepal pledged $1m (£660,000) in initial aid while the US Agency for International Development sent an urban search and rescue team.

"We are working closely with the government of Nepal to provide assistance and support,'' said Secretary of State John Kerry.

China on Sunday dispatched a 62-member search and rescue team.

Epicentre of the quake

A number of international charities including Red Cross, Oxfam, Doctors Without Borders and Christian Aid are also sending teams to quake-hit areas.

"We do not yet know the scope of the damage, but this could be one of the deadliest and most devastating earthquakes since the 1934 tremor which devastated Nepal and [the Indian state of] Bihar," said International Federation of the Red Cross and Red Crescent Societies (IFRC) Asia-Pacific Director Jagan Chapagain.

The IFRC said it was especially worried about the fate of villages near the epicentre of the quake, some 80km (50 miles) from the capital Kathmandu.

In Europe, Britain, Germany and Spain pledged assistance, with Norway pledging $3.9m in humanitarian aid.

"The absolute priority must be to reach people who are trapped and injured, and provide shelter and protection to those who have lost their homes," UK International Development Secretary Justine Greening said.

Foreign climbers and their Nepalese guides around Mount Everest were caught by the tremors and a huge avalanche.

As well as the 17 confirmed deaths, 61 people were injured when part of the base camp was buried under snow.

Helicopters trying to airlift the injured to Kathmundu were delayed by cloudy weather, but have now managed to land at the base camp.

Dan Fredinburg, a Google executive who described himself as an adventurer, has also been killed, Google confirmed.

BBC/TF