A strong undersea earthquake rocked Indonesia’s Aceh province early Wednesday, killing at least 54 people and sparking a frantic rescue effort in the rubble of dozens of collapsed and damaged buildings, The Wall Street Journal reported.

Maj. Gen. Tatang Sulaiman says 52 have died in Pidie Jaya, the district closest to the epicenter of the undersea quake. Another two people died in neighboring Bireuen district. The national disaster mitigation agency said 78 people have suffered serious injuries.

The rescue effort involving villagers, soldiers and police is concentrated on Meureudu, a severely affected town in Pidie Jaya district. Excavators were trying to remove debris from shop houses and other buildings where people were believed buried.

The U.S. Geological Survey said the shallow quake struck at 5:03 a.m. local time, centered about 10 kilometers (6 miles) north of Reuleut, a town in northern Aceh, at a depth of 17 kilometers. USGS later Wednesday increased the magnitude of the earthquake to 6.5 from an earlier figure of 6.4. The quake did not generate a tsunami.

Pidie Jaya district chief Aiyub Abbas said 25 people had been killed and hundreds injured in that district alone. A local health office said eight of those who died were young children.

Mr. Abbas said more than 40 buildings, including mosques, stores and homes, were flattened in the area about 18 kilometers (11 miles) southwest of the epicenter. Roads cracked and power poles toppled over. TV footage showed rescue personnel taking bodies in black bags away from the rubble.

There is an urgent need for emergency supplies and excavation equipment to move debris, Mr. Abbas said.

In the nearby Bireuen district, a teacher at a building school died after being hit by falling debris, and about 20 people were being treated for injuries, said health worker Achmad Taufiq.

People in the town of Lhokseumawe ran out of their houses in panic during the quake and many people fled to higher ground.

In the capital Jakarta, President Joko Widodo said he has ordered all government agencies to take part in rescue efforts.

Indonesia, the world’s largest archipelago, is prone to earthquakes because of its position on the Pacific “Ring of Fire,” an arc of volcanoes and fault lines in the Pacific Basin.

In December 2004, a massive earthquake off Sumatra island triggered a tsunami that killed 230,000 people in a dozen countries. More than 100,000 died in Aceh after that earthquake.

“It was very bad, the tremors felt even stronger than 2004 earthquake,” Musman Aziz, a Meureudu resident, said of Wednesday’s quake. “I was so scared the tsunami was coming.”