Raging waters swamped part of China's largest oil field Thursday, forcing 100,000 people to flee nearby villages and cutting a railway line needed for bringing in relief supplies.

Thousands of soldiers struggled to fortify the 170 miles of dikes surrounding the Daqing oil field in China's northeastern province of Heilongjiang. Experts warned the dikes were in critical condition after being waterlogged for weeks, the China Daily reported.Vice Premier Wen Jiabao, under orders from Communist Party leader Jiang Zemin, stood near a dike to exhort the soldiers with a bullhorn, reminding them of what is at stake.

The government-controlled media have given little information about flood damage or deaths and instead have been ordered to play up flood-fighting efforts.

Still, more than 2,000 people have died nationwide in flooding in recent weeks. Economic losses are expected to reach $24 billion - including damage to the Daqing field, which accounts for at least a third of China's oil production.

In Harbin, a city of 9 million people 100 miles southeast of Daqing, soldiers marched through the streets holding red flags and singing as they went to patrol a 6-foot-high dike of sandbags protecting the city from the swollen Songhua River.