Minister Ram Sharan Mahat based the death toll on reports from the Nepalese Army.
Hundreds of people died and many more were feared trapped in rubble Saturday after a magnitude-7.9 earthquake devastated Nepal's capital and provoked a caused a deadly avalanche on Mount Everest.
The earthquake hit at 0611 GMT, with its epicentre about 80 kilometres north-west of Kathmandu, according to the United States Geological Survey (USGS).
A spokesman for the Nepalese Interior Ministry said the provisionaldeath toll stood at around 888. The figure is likely to be higher given that many people are believed to buried under rubble, including in remote areas. More than 1,800 had been injured.
As night fell in Kathmandu, residents prepared to sleep on thestreets. Some had lost their homes and others feared aftershocks.
The ancient historic centre of the city was a picture of devastation. Roads cracked wide, rescue workers and families scrambled for missing loved ones among buildings collapsed into rubble and crowds outside hospitals where beds with injured spilled onto the streets.
Large swathes of the city had no electricity and communication lines were hit.
The tremor was the worst to hit Nepal since 1934, when a similarly powerful quake killed 17,000 people, mostly in Kathmandu.
The government declared a state of emergency in the areas affected bythe earthquake and appealed for humanitarian assistance.
The earthquake was also felt in India, China, Pakistan and Bangladesh. More 40 deaths were reported in those countries, with most of the casualties occurring in India's eastern Bihar state, which borders Nepal.
Most of the deaths were caused by building and wall collapses.
Indian Prime Minister Narendra Modi held an emergency meeting and the country started airlifting rescue and relief material and personnelto land-locked Nepal which sits along the Himalayan range.
India has sent four tons of supplies - food, water, communicationssystems and other equipment and 40 trained rescue personnel to Nepaland plans to send two more aircraft with medical supplies and doctors, an Indian Defence Ministry spokesman said.
Russia said it would send some 50 rescue personnel.
"There is devastation everywhere. I saw two people get hit by bits ofa falling building and die in New Road," said Yogesh Sitaula as he walked through the city. "There are fallen buildings and walls all over. People are being treated on streets. Hospitals are crammed."
The city's international airport was briefly closed as a precaution,with flights diverted to airports in India.
No commercial flights were operating from the Kathmandu airport, but Indian aircraft with relief materials and rescue equipment werelanding, India's Foreign Secretary S Jaishankar said.
Buildings in Durbar Square, a UNESCO World Heritage site in the centre of Kathmandu, were destroyed, leaving mounds of timber andrubble, Nepal's Kantipur television reported.
"I saw people who were very scared but also helping each other. A lot of people are feared buried under these old houses, some of them are100 years old," Kathmandu-based journalist Kashish Shreshtha added.
"Kathmandu Durbar Square, a historic UNESCO heritage site, has turnedinto a rubble. All the temples are destroyed. There was a blood donation camp ongoing at one of the heritage sites. The buildingcollapsed and it seems everyone is dead," Shreshtha added.
At another location, a Christian congregation of some 40-50 members were buried under the rubble when the earthquake destroyed the building where the church stood, Shyam Krishna, Kathmandu resident said.
"They (the congregations) were in the sixth floor in the seven storey building, and the whole building turned to dust. The congregation wasmeeting for their weekly Saturday service. It seems no one survived,"Krishna said.
The earthquake also triggered avalanches on Mount Everest, a populardestination for climbers. At least eight people were killed in one such avalanche near the Everest base camp.
"The communication is not very good up there, and the toll couldstill go up," Gyanendra Shrestha, a tourism official, told dpa.
"We are not certain about the nationality of those killed. Several hundred climbers were in the base camp area."
Daniel Mazur, a climber, said on Twitter that the camp had been"severely damaged."
Nepal's Prime Minister Sushil Koirala cut short his trip to Bangkok and Jakarta, where he was due to attend a meeting of Asian and African leaders on Sunday.