It comes after an earthquake on April 25 killed more than 8,150 people and injured more than 17,860 as it flattened mountain villages and destroyed buildings.
Tuesday's quake was deeper, however, coming from a depth of 18.5 kilometers (11.5 miles) versus the April 25th quake that hit 15 kilometers (9.3 miles). More shallow earthquakes tend to cause more damage at the surface.
It was followed closely by two aftershocks — measuring magnitude 5.6 and 6.3 — within 30 minutes.
"The shaking seemed to go on and on," said Rose Foley, a UNICEF official based in Kathmandu. "It felt like being on a boat in rough seas."
Aid agencies were still struggling Tuesday afternoon to get reports from outside of the capital.
"We're thinking about children across the country, and who are already suffering. This could make them even more vulnerable," Foley said.
In the capital of Kathmandu, the quake sent people rushing outside of their homes. Police gave no immediate estimates of damage.
Strong shaking was also felt across northern India. In the Indian capital of New Delhi, people scrambled outdoors while buildings swayed.
Nepalese have been terrified by dozens of aftershocks that hit the country in the days following the April 25 quake. Meanwhile, the impoverished country has appealed for billions of dollars in aid from foreign nations, as well as medical experts to treat the wounded and helicopters to ferry food and temporary shelters to hundreds of thousands left homeless amid unseasonal rains and unreachable with landslides blocking many mountain roads.