Four were killed in Sindhupalchowk, which suffered the heaviest death toll in last month's quake.

Just when life was returning to normalcy in cities and quake-affected people in several villages trying to build temporary shelter, another strong tremor hit parts of Nepal and several parts of India.

Immediately after tremor shook the ground and people came out on to the streets in panic, Prime Minister Sushil Koirala appealed for calm and not to run after “rumours of another earthquake”.

Addressing a press conference immediately after holding an emergency Cabinet meeting, PM Koirala said the all should come together to face this big crisis.

According to police, at least 57 people were killed and over 1,100 injured in three districts of the capital and nine outside. The aftershock affected altogether 32 districts on Tuesday, destroying several houses and buildings. Strong tremors were felt in India as well, with even Chennai residents feeling the tremor.

The jolt, coming a little over two weeks after the earthquakes of April 25 and 26, led to panic, with people coming out onto the streets. By 5 p.m., several open spaces, road islands (with green patches), fields and temples were full of make-shift and proper tents. People said they were going to sleep out in the open. Many had done so for over a week after the April 25 earthquake, but most had returned to their house in the last few days.

The April quakes have so far killed over 8,000 people and left more than 17,000 injured.

Ministry of Home Affairs said the epicentre of the earthquake – which, according to USGS was 7.3 magnitude – was between Jhyakusuri and Chilankhako in Dolakha district, north east of Kathmandu.

Of the 57 who died on Tuesday, 34 occurred in Dolakha, which borders Sindhupalchowk, the worst-hit district in the quakes of April 25 and 26.

Throughout the day there have been major and minor aftershocks. Of these six were between 5.3 and 6.2 magnitude.

At several places in the Kathmandu Valley and outside, the buildings that had developed several big cracks or were tilting to one side, collapsed, reports said.

A 5-storeyed building in Naya Bazar in Kathmandu, which had been damaged on April 25, collapsed. DSP Sitaram Rijal who was on the spot said that they had cordoned off the building. “So I don’t think people got trapped inside,” he told The Hindu.

At nearby Balaju, a woman was killed when another 5-storeyed building collapsed.

Some labourers who were repairing houses got injured after the quake hit. The Hindu correspondent saw an injured man being brought to Tribhuvan University (TU) Teaching Hospital in Kathmandu, with both of his legs in plaster.

Another labourer, Prem Bhadaur Magar, was in Indrachowk area, one of the most densely populated, with old houses and choc-a-bloc section inhabited by Newai community when he felt the bamboo frame shaking wildly. “We were demolishing a damaged 4-storeyed house when the earthquake happened,” Mr. Magar said. “I jumped from the first floor. He was unhurt.

The government has extended the closure of educational institutions by a further two weeks. They had been ordered shut after April 25 and a review was to be taken on May 14, the last day of the Nepali month of Baisakh.

Meanwhile, the Tribhuvan International Airport in Kathmandu was closed for about two hours after the jolt. It resumed operation from around 3 p.m. local time.

The Hindu's extensive coverage of the earthquake that struck Nepal on April 25, 2015.