The quake occurred at 4:35 a.m. local time, 20 miles west-northwest of Imphal, India, the capital of Manipur state, the USGS said. The USGS initially reported a preliminary of 6.8 magnitude before revising the assessment about an hour later.
There were reports of damage to a popular market in Imphal, the capital of Manipur state. The tremor left large cracks in several walls and a portion of the building collapsed, police said.
India's Meteorological Department said the epicenter of the quake was in Tamenglong region of Manipur state. It struck before dawn on Monday at a depth of 17 kilometers (about 10 miles) in the India-Myanmar border region. The U.S. Geological Survey said the depth was 55 kilometers (about 34 miles).
The epicenter of the earthquake was 35 kilometers (20 miles) northwest of Imphal.
People panicked and rushed out of their homes in Gauhati, the capital of neighboring Assam state, as they felt massive shaking at least twice within 60 seconds.
In Imphal, residents said furniture was knocked over and books fell off shelves but no major damage has been reported so far.
"The ground swayed for almost a minute, jolting people awake in their homes," said one resident, Apem Arthur.
The area is dotted with small houses. There are few tall buildings in the region, she said.
The tremors were also felt in Kolkata, the capital of West Bengal state.
