Five days after an embarrassing chemical spill, China's government celebrated the return of running water to this city of 3.8 million as a victory for the communist system while warning the water was still not safe to drink.

The spill was a political disaster for President Hu Jintao's government and cast a harsh light on the environmental costs of China's breakneck development.

Hu's government issued apologies to China's public and to Russia, where a border city downstream is bracing for the arrival of the 50-mile-long benzene slick.

State media have accused officials of lying about and trying to conceal the spill — the result of a Nov. 13 chemical plant blast in Jilin, a city upstream from Harbin, that killed five people and forced 10,000 more to flee their homes.

But on Monday, media coverage was effusively upbeat, with newspaper photos showing smiling children in Harbin running their taps and water surging through treatment plants.

"We won!" said a headline in the newspaper Life News below a photo of the provincial governor drinking a glass of boiled tap water on Sunday.

But officials warned that the water wasn't immediately safe to drink, or bathe in, after lying in underground pipes for five days. They said they would let the public know when the water was potable again but gave no indication with that would be.

"It's back, but I don't know what I can use it for yet," said Guan Hongya, a manager for a textile company. "We can use it to flush the toilet, but otherwise it might be no good."

Premier Wen Jiabao has promised to investigate the disaster and punish those responsible. But state media also have been portraying efforts to keep this major industrial city supplied with drinking water as a triumph for the communist system.

On Monday, some residents were still lining up in sunny but subfreezing weather to get drinking water from fire trucks and tankers sent by state companies.

State television in Heilongjiang province broadcast a variety show featuring young women in jade-green costumes dancing with empty 10-gallon water bottles on their shoulders. A comedian played with a giant squirt gun. Harbin is the capital of the province in China's frigid northeast.

The audience included provincial Gov. Zhang Zuoji, local officials and paramilitary police who had helped to distribute water. Banners behind the stage showed the names of nearby cities that sent fleets of water trucks to Harbin.

There was no immediate announcement of when public schools, shut since last week, would reopen.

The pollutants were expected to reach Russian territory within days and Khabarovsk, a city of 580,000, within weeks. The Songhua flows into the Heilong River, which crosses the border and becomes the Amur in Russia.

A group of Russian experts flew to Harbin on Monday to check on the spill's location and pollution levels, the RIA Novosti news agency reported.

Russia's Emergency Situations Ministry said Monday it was preparing to shut off running water and would airlift activated carbon to help water treatment facilities along the Amur River absorb the spill.

Emergency Situations Minister Sergei Shoigu said later the deadly chemical could flow into Russia within the next two weeks. He said officials were ready to block running water and start water deliveries.

Vladislav Bolov, a ministry official in charge of efforts to respond to the spill, said Monday the benzene concentration in the Amur most likely will be up to 10 times greater than normal.

"We have built up supplies of drinking water," Bolov said at a news conference, according to the ITAR-Tass news agency.

Gennady Onishchenko, Russia's chief sanitary official, urged Khabarovsk residents to create water reserves at their homes before the running water was shut off.

Environmentalists have criticized China's response to the spill and questioned the decision to allow a facility handling such dangerous materials near a key water source.

The plant is operated by a subsidiary of China's biggest oil company, state-owned China National Petroleum Corp., which has apologized for the disaster.

The announcement that Harbin would suspend water service triggered panic-buying of bottled water, soft drinks and milk. Schools closed and residents stocked up on water in bathtubs and tea kettles.

But despite the initial anxiety, many took the water cutoff stoically, lining up in biting cold for supplies from trucks.

China has suffered a string of such disasters in recent years, each leading to official promises of more rigorous enforcement of environmental rules or more sensitivity to public worries.

Industrial pollution is a sensitive issue, with protests reported nationwide over complaints that factory discharges are ruining crops and local water supplies.

Protesters often accuse officials of failing to enforce environmental standards, either in exchange for bribes or for fear of harming economic growth. The government says all major rivers are dangerously polluted, threatening water supplies for millions.

With its huge population, China ranks among countries with the smallest water supplies per person. Hundreds of cities regularly suffer water shortages.