Most of the 8,000 children found alone after China's devastating earthquake have been reunited with their parents, Chinese officials said Friday.

About 1,000 have not been spoken for but the need to find adoptive families is now far less than earlier thought, said Ye Lu, a senior official at the Civil Affairs Department in hard-hit Sichuan province.

Officials have been deluged by offers from within China and overseas to adopt orphans from the May 12 quake , but the need was now far less than was earlier thought, said Ye Lu, a senior official at the Civil Affairs Department in devastated Sichuan province.

"We are still getting thousands of calls per week asking about how to adopt, but we are still hoping to find the parents of these 1,000 kids," Ye said.

More than 18,000 people are still listed as missing more than two weeks after the quake, which crumbled scores of towns and left 5 million people homeless scattered across hardest-hit Sichuan province.

The government on Friday raised the confirmed death toll to 68,858. Officials expect the final tally to top 80,000.

Separately, officials upgraded the threat posed by waters rising quickly behind a mass of rocks and earth that tumbled from a mountainside when the tremor struck and blocked a river running through a valley dotted by dozens of villages.

Troops are moving almost 200,000 people who are in the direct path of the potential flood to higher ground — many of whom are already living in tents or other temporary shelters after their homes were destroyed.

Officials also said they had a plan to evacuate a total of 1.3 million people in and around Mianyang, a city that could face flooding, within five hours if the dam wall breaks.

An official with the press office of Mianyang City Quake Control and Relief Headquarters said authorities would run a drill for three days starting Saturday.

The drill would consist of testing the command system of various levels of government officials to ensure that any order to evacuate — if it comes — would be passed on quickly to everyone in the valley, said the official who would only give her surname of Chen.

"Not all 1.3 million people will be actually evacuated," Chen told The Associated Press. "People will only be evacuated in case of the actual collapse of the whole bank."

A report earlier Friday by the official Xinhua News Agency that all 1.3 million had been ordered to evacuate from the valley was wrong, Chen said.

She said 197,500 people in the valley are being moved to higher ground — about 30,000 more than officials had announced in recent days.

Hundreds of troops using 40 bulldozers and heavy excavating machines are working around the clock at the lake, named Tangjiashan, to dig channels that will drain the lake safely.

There was no sign that the lake dam was close to bursting Friday, though officials say it could do so in coming days.

Tangjiashan is the largest of more than 30 lakes that have formed behind landslides caused by the quake, which also weakened man-made dams in the mountainous parts of the disaster zone.

Many of the 5 million left homeless are living in tent camps or prefabricated housing being erected by troops, which are taking on the tone of new villages.

In one camp at Mianzhu, hospitals, schools and even a makeshift shopping mall had emerged, along with stores selling shampoo, shoes, beer and clothes.

A mobile medical center on the back of a tractor-trailer rig offered free eye exams. About 50 people — mostly senior citizens and children — lined up for the checkups.

"I've never had my eyes checked before. Even before the quake. This is the first time," said Yu Xiaoling, a 54-year-old farmer who lost her home in the quake.

But some residents were longing for the comforts of home.

"Life is really good here, but we don't have a TV. The things I miss most, though, are my stuffed animals. I lost them when our home collapsed," said Fang Ming, a 10-year-old girl standing outside her tent peeling an orange with the sharp edge of a chopstick.

Repair and recovery work continued, including pulling down damaged buildings. Troops have also been spraying disinfectant on the rubble and in survivor camps — an attempt, they say, to reduce the risk of disease breakouts.

But Dr. Claude de Ville de Goyet, a medical consultant who frequently works at disaster sites, said spraying bleach on the rubble would have no effect except a psychological one on victims. "It's cosmetic," he said.

A stockpile of bleach being used as disinfectant ignited on Thursday, injuring several soldiers who helped extinguish the blaze.

Meanwhile, Japan said it had decided not to use military planes to deliver aid to the quake zone, after Beijing voiced uneasiness over the mission. The aid would be delivered by civilian charter flights instead, Chief Cabinet Secretary Nobutaka Machimura.

Beijing had been in talks with Tokyo about using Japanese military planes to deliver aid, which could have become the first significant military dispatch between the two nations since World War II.

Japan invaded China and conquered large parts of it in the 1930s before being defeated by the Allies in 1945, still a sensitive issue to both countries.

China Red Cross deputy director Jiang Yiman promised monthly audits of its relief operations, seeking to address concerns that some of the billions of dollars donated to help quake victims could be siphoned off by corrupt officials.