BEIJING — The collapse of an under-construction railway bridge over a major river in China has killed at least 12 workers and left four others missing, state media reports said.

Aerial photos from the official Xinhua News Agency show a large section missing from the bridge's curved aquamarine arch. A bent section of the bridge deck hangs downward into the Yellow River below.

Sixteen workers were on the bridge in northwest China's Qinghai province when a steel cable snapped about 3 a.m. Friday during a tensioning operation, Xinhua said. Boats, a helicopter and robots were being used in the search for the missing., This news data comes from:http://tg.gangzhifhm.com

The bridge is 1.6 kilometers (1 mile) long and its deck is 55 meters (180 feet) above the surface of the river below, the English-language China Daily newspaper said.

Chinese bridge collapse kills at least 12 construction workers