Soldiers were ordered to deepen a diversion channel to speed the draining of an unstable earthquake-formed lake that was threatening to burst, state television said Friday.

Workers have already dug a 1,300-foot-long spillway to release pressure on the unstable wall of mud and rock restraining the Tangjiashan lake.

However, as of 8 a.m. Friday, the water level in the lake remained 2 feet beneath the spillway, prompting the order to deepen the 36-foot channel, state broadcaster CCTV said in its noon news broadcast.

Technicians were keeping a wary eye out not just for increased rainfall but also landslides that could set off a flood surge in the lake. The lake was created when landslides set off by the magnitude 7.9 quake on May 12 blocked a river.

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Along with communities downstream, the lake also threatens a key oil pipeline belonging to state-owned China National Petroleum Corp. just 37 miles away, the company said in a news release.

General Manager Jiang Jiemin had flown to the scene to oversee measures to protect the pipeline, billed as the longest and widest in China.

More than 250,000 people in low-lying areas about 30 miles downstream had been evacuated as of Thursday, according to state media.

An estimated 10,000 people moved from low-lying areas were camping among trees, pagodas and tea houses in a hillside park outside the downstream city of Mianyang. Authorities were distributing instant noodles, water and biscuits, while some families prepared meals with electric rice cookers plugged into extension cords.

"All I do every day is eat noodles, listen to the radio and sleep," said retiree Zhen Yiyuan, who wondered if authorities had moved too hastily in forcing people to leave more permanent camps as early as May 28.

Still, Zhen said his sister living in the destroyed mountain village of Yuli had it far worse, surviving only on salvaged corn and other crops after the few pounds of rice airdropped after the quake ran out.

Zhang Jingping, 40, who works at the highway bureau, complained of the 86-degree heat and mosquitoes, and said he had recently made the 125-mile roundtrip journey to the provincial capital of Chengdu just to check into a hotel room and take a shower.

"This is what it's like to be a refugee," said Zhen, sitting under a plastic sheet strung between two trees. "Who knows when life will get back to normal."

Amid scattered complaints of misuse of quake aid, the government's National Audit Office announced it would "investigate and deal with any attempt to hide, intercept or misappropriate" donated funds and materials, Xinhua said.

Domestic and foreign donations had reached $6.33 billion as of midday Thursday, Xinhua said. It said the audit office's report would be issued around June 20.

The May 12 quake killed 69,127 people, with 17,918 still missing, according to the latest government figures.

As of May 20, authorities recorded 4,700 unclaimed children whose parents presumably died in the quake, Civil Affairs Ministry official Zhang Shifeng said at a news conference Friday. However, Zhang said he expected the final number of orphans to number 1,000-2,000 as children were gradually handed over to members of their extended families.

Zhang said parents from around China were showing huge interest in adopting quake orphans, with 10,000 families registering for adoption in one province alone. He indicated the ministry could give priority to parents who lost their own children in the quake.

"Experts say that it is easier to establish the relations for those who lost their kids to adopt those who lost their parents," he said.

Engineers and building experts sent to the disaster zone to study damage have raised questions about poor construction, bad urban planning and lack of enforcement of building codes. The problems were especially glaring at some schools and in rural areas and small towns, they said.

"My feeling is that if the construction work in general had been better, then the loss could have been minimized," said Chen Baosheng of Tongji University, who studies disaster prevention in buildings.

Growing public anger over the deaths of children in more than 7,000 collapsed schoolrooms has fueled accusations about corruption in school construction, putting the government on the defensive.

Authorities have promised to investigate the school collapses in Sichuan province, but there has not been any word on findings. Officials were analyzing samples of the debris but said the work would take time.