At least 42 people have been killed after a severe earthquake hit Nepal, just weeks after an earlier severe seismic movement killed thousands in the mountainous nation.

Powerful aftershocks have hit the ravaged nation, measuring at magnitudes of 5.6, 5.4 and 6.3.

At least 36 people were killed in Nepal, according to national police spokesman Kamal Singh Bam who put the number of injured at 679.

A powerful earthquake shook eastern Nepal on Tuesday, shattering the halting recovery from the earthquake that hit the country less than three weeks ago, and causing loose hillsides and cracked buildings to give way and collapse.

By late afternoon, Nepal’s National Emergency Operation Center had reported 42 deaths and 1,117 injuries from Tuesday’s earthquake, which the United States Geological Survey assigned a preliminary magnitude of 7.3. The death toll from the April 25 earthquake, with a magnitude of 7.8, has reached 8,159 and continues to rise.

Residents and office workers ran screaming into the streets when the temblor struck, shortly after noon, and people described clouds of mud and dust rising up as cracked structures fell. Prakash Banjara, an engineering student, was on an aid mission with 15 other students, delivering rice to remote villages in Sindhupalchowk District, when “the earth started shaking so violently.”

“The mountains before my eyes started tumbling down in massive landslides,” Mr. Banjara said by telephone. He begged for help for his small group of volunteers, now stranded by landslides on an isolated road, unable to contact the police and fearing the approach of a predicted storm.

The epicenter of Tuesday’s earthquake was about 50 miles east of Kathmandu, near the border with China, whose towns and villages were also devastated by the April 25 quake. The largest cluster of deaths, 19, was registered in the district of Dolakha, a mountainous and sparsely populated region where the elevation reaches 7,314 meters, or just under 24,000 feet. Seventy-seven people in Dolakha died in the April 25 earthquake, officials said.

Gajendra Thakur, who oversees relief work for the district, described conditions in Dolakha as “very, very severe.”

The country’s exhaustion was evident in a message sent via a government Twitter account about two hours after the earthquake.

“Pray to Almighty: Keep all Nepalese safe in this difficult period of time,” read the message, sent from the Nepal Emergency Operations Center.