Workers are busy breaking up a frozen section of the Yellow River in north China's Inner Mongolia Autonomous so it will not block approaching ice runs and lead to flooding.

Yan Xingguang, spokesman of the Inner Mongolia Yellow River Ice Runs Control Headquarters, said floating ice chunks about 1 kilometer long were 30 kilometers away from the Haibowan Water Conservancy Project under construction in Wuhai City on Monday, where ice-breaking work was underway.

He said workers were using iron boxes filled with rocks to smash through the ice at the Haibowan section.

The Yellow River, China's second longest, freezes and thaws at different times, posing flood risks mainly in Inner Mongolia and east China's Shandong Province.

This winter a 906-kilometer long section of the river in Ningxia Hui and Inner Mongolia autonomous regions had frozen, said Yan.

As the temperature picked up in early March, 225 kilometers of the frozen section in Ningxia partly thawed and started to flow downstream towards Inner Mongolia. The frozen part of the river in Inner Mongolia is expected to completely thaw by the end of March.

Yan said the river near the Haibowan Water Conservancy Project was still ice-covered.

In the section of the Yellow River near Wuhai City and Bayan Nur City, ice bombing has been carried out every year to remove blockages and prevent flooding.

The last time an ice flow caused the Yellow River to flood was in March 2008 in Hangjin Banner. Eleven villages and a township seat were flooded, causing the evacuation of around 13,000 people, and about 20,000 homes were destroyed and more than 33,000 livestock killed.

Yan said the Haibowan Water Conservancy Project in Wuhai would help stop floods caused by ice runs after it is completed in 2013. A diversion channel will divert the river's ice flows into a reservoir with a water holding capacity of 487 million cubic meters, he added.