HONG KONG — Rescuers in Taiwan searched badly damaged buildings Wednesday looking for scores of people left missing after a powerful earthquake hit the island’s east coast.

The magnitude-6.4 quake struck at 11:50 p.m. Tuesday and was centered 14 miles northeast of the coastal city of Hualien. The shaking was felt across Taiwan, but in Hualien the force was disastrous, collapsing walls and leaving buildings resting at alarming angles.

On Wednesday a clearer toll emerged: five dead and dozens of people feared trapped, officials said.

“Thank you to our first responders for their tireless efforts in #Hualien,” President Tsai Ing-wen, who visited the disaster scene Wednesday, wrote on Twitter. “Rescue operations have been continuing night & day. Right now 145 people remain unaccounted for — we will not rest until all are found.”

As survivors were pulled from damaged buildings during the day, the number of people believed missing dropped to 88 from 145 by 3 p.m. More than 250 people were injured, officials said.

Most of the missing were trapped in a large building with both businesses and apartments in downtown Hualien. The gray tile and glass Yun Men Tsui Ti building, which sits next to a park along the Meilun River, had a small hotel, a hot pot restaurant and apartments. The authorities believe more than 200 people were in the building during the quake, which flattened parts of its lower levels and left it leaning precariously. The bodies of the four who died were pulled from the building, as were dozens of survivors.

The bottom floors of another building, the Marshal Hotel, also collapsed. One person was killed there and two were missing, officials said.

Taiwan sits at the intersection of the Philippine Sea tectonic plate, which is moving west at about three inches a year, and the Eurasian plate, which extends east from mainland China. It is an area of frequent seismic activity, and earthquakes are common.

The mountainous east coast of Taiwan is less populated than its flatter western side. The region is known for its natural beauty. Hualien is close to Taroko National Park, where the famous Taroko Gorge cuts down through the mountains to the sea.

More than 90 weaker earthquakes were measured along Taiwan’s east coast in the week before Tuesday’s quake, the Central Weather Bureau reported. More than 100 aftershocks have been recorded since it struck, and the authorities warned that earthquakes of magnitude 5.0 or higher were possible over the next two weeks.

Two strong earthquakes of magnitude 5.3 and 6.1 were recorded within 45 minutes of each other on Sunday night near Hualien. The pattern of seismic activity that followed was stronger than anything that had previously been recorded in the area, Chen Kuo-chang, the acting director of the Central Weather Bureau’s Seismology Center, told the state-owned Central News Agency.

“This is unprecedented and not a normal release of energy,” he said.

While earthquakes are common in the area, the geology makes it rare to have many quakes in short succession, Mr. Chen said.

Tuesday’s earthquake in Hualien hit two years after an earthquake in southern Taiwan leveled a 17-story building in Tainan City, killing 117 people.