Turkey's main seismography center says the 7.2-magnitude quake that hit the east of the country could have killed up to 1,000 people.
The Kandilli observatory's estimate is based on the strength of the quake and the structure of the housing in the area.
"We are estimating a death toll between 500 and 1,000," Mustafa Erdik, head of the Kandilli observatory, told a televised news conference Sunday.
The deputy prime minister says around 45 buildings have collapsed in the town of Ercis and the city of Van. Ercis sits on a geological fault line.