Rescue workers in Turkey's Van region continue to pull survivors from the rubble after a 5.7 magnitude earthquake late Wednesday killed at least 12 people and caused more than 25 buildings to collapse.

Officials said Thursday all but three of the buildings were empty after being evacuated following a 7.3-magnitude quake that hit the Van region on October 23.

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 believe other survivors could still be trapped in the wreckage and dozens of angry residents clashed with police to show their displeasure over relief efforts. Riot 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.