A 6.9-magnitude earthquake struck the island of Sumatra in western Indonesia on Saturday, according to the US Geological Survey, just hours after a 7.7-magnitude earthquake hit the Southeast Asian country. The epicenter of the earthquake was located in Pematangsiantar, about 126 kilometers southeast of the island's capital, Medan. No tsunami warning was issued. The previous earthquake, which struck the east of the country on Saturday morning, killed 38 people.