Rescue workers in Turkey are again searching for survivors of an earthquake less than three weeks after a 7.3-magnitude quake hit the Van region that killed around 600 people and left thousands homeless.

A 5.7-magnitude earthquake shook Van late Wednesday, collapsing at least 25 buildings. Officials say all but three were empty after being evacuated following the October 23 earthquake, but at least eight people were killed in Wednesday's temblor.

Turkey-born Ayhan Irfanoglu (I-fahn ear-FAN-oh-loo), a civil engineer at Purdue University in the midwest U.S. state of Indiana, was in Turkey to help determine why the damage was so extensive after the October 23 quake. He says there were design and construction errors.

But Irfanoglu does not believe the recent quakes will lead to a change in building codes.

He believes better training of inspectors is the key.

Rescue workers have also pulled at least 25 survivors from the rubble. But many are still believed to be trapped in the wreckage and dozens of angry residents clashed with police to show their displeasure over relief efforts. Police responded with tear-gas and batons. Many of the survivors from the first quake are still living in tents or make-shift open-air camps as temperatures continue to drop.

State television reported that among the newly toppled buildings was a six-story hotel, which was used by foreign journalists and aid workers.

The U.S. Geological Survey says the epicenter Wednesday was about 15 kilometers from Van province, which was devastated by the October earthquake.

It is not clear if Wednesday's quake was a strong aftershock.