The bulk of the fatalities were reported in China's southwest province of Sichuan.
The quake, measuring 7.8 on the Richter scale, was the worst to hit the country in more than three decades, and affected eight provinces, devastating buildings and infrastructure, leaving thousands of people buried alive under rubble.
Some 60,000 people are said to be unaccounted for near the epicenter of the quake, which was located some 60 miles (96 km) northwest of Sichuan's provincial capital, Chengdu.
It was earlier reported that over 900 students had been trapped under rubble after a three-story school collapsed in the Sichuan city of Dujiangyan. The quake also brought down two chemical plants in the province, the buildings burying hundreds of workers and spilling more than 80 tons of toxic liquid ammonia.
The earthquake struck on Monday at 2:28 p.m. local time (06:28 GMT). Tremors were also felt some 930 miles (1,500 km) away in the capital, Beijing, where office workers rushed out into the streets as their buildings shook.
An estimated 17,000 Chinese soldiers and 34,000 military are involved in the ongoing disaster relief operation.
Russia's new president, Dmitry Medvedev, sent a message to Chinese President Hu Jintao on Monday offering help in rescue and reconstruction efforts.