At least 11 people were killed and more than 30 went missing when a bridge on a highway collapsed partially due to flash floods in China's Shaanxi province, authorities said on Saturday.

The bridge, located in Zhashui County in Shangluo City, collapsed on Friday evening due to a sudden downpour and flash floods, the state-run Xinhua news agency reported, quoting the provincial publicity department.

Eleven people were confirmed dead as of Saturday morning, while more than 30 went missing after the collapse, the report said.

The collapse caused some vehicles to plunge into the Jinqian River below the bridge, it said.

The exact number of vehicles involved in the collapse is still being determined.

It added that rescue teams recovered five vehicles that had fallen into the river, and rescue operations were underway.

According to the Ministry of Emergency Management, a team was dispatched to guide rescue efforts.

The China National Comprehensive Fire and Rescue Team sent 736 people, 76 vehicles, 18 boats and 32 drones to carry out rescue efforts, it said.

Chinese President Xi Jinping urged all-out rescue and relief efforts to "safeguard people's lives and property after the bridge's collapse," the report said.