KATHMANDU, Nepal — A major earthquake hit a remote mountain region of Nepal on Tuesday, killing at least 37 people while triggering landslides and toppling buildings less than three weeks after the Himalayan nation was ravaged by its worst quake in decades.

The magnitude-7.3 quake — centered midway between the capital of Kathmandu and Mount Everest — hit hardest in districts northeast of the capital. It terrified a nation already shell-shocked and struggling after a more powerful quake on April 25 killed more than 8,150 and flattened entire villages, leaving hundreds of thousands homeless.