Heavy damage from Monday's devastating earthquakes near the Turkish-Syrian border is complicating the search for survivors.

The death toll in the countries has passed 11,000. It's the first natural disaster to kill more than 10,000 people since the March 2011 earthquake and tsunami in Japan.

Turkish President Recep Tayyip Erdogan visited the hard-hit city of Kahramanmaras on Wednesday. He has declared a three-month state of emergency in 10 provinces to speed up rescue work.

The World Health Organization estimates as many as 23 million people in Turkey and Syria could have been affected.

Many have been left homeless. They are pleading for warm clothing and medical supplies as temperatures dip below freezing in some stricken areas.

In northwestern Syria, a newborn baby girl was pulled alive from the rubble. She was still attached by her umbilical cord to her mother. Her parents and siblings did not survive.

The quakes leveled buildings across vast swaths of Turkey. University of Tokyo Professor Kusunoki Koichi, an expert on earthquake engineering, said an apparent cause of the extensive damage was that the violent shaking caused building pillars to break instantly as if they had exploded, and that caused floors to collapse down onto each other. Kusunoki said the phenomenon called "pancake collapse" occurred at several locations.

Several apartment buildings collapsed in the same direction. Kusunoki said this suggests they were toppled by a sudden powerful jolt. He said further analysis is needed.

Kusunoki said Turkey's building standards are on par with Japan's. But code enforcement is another matter. A study by the Turkish Parliament found about 6.7 million buildings were not up to code as of 2021.