Harbin, China ? Visiting Premier Wen Jiabao ordered local leaders to restore running water to the 3.8 million people of this northeastern Chinese city, who spent a fourth day Saturday without supplies after a chemical spill in the river that provides their water.

The foreign minister, meanwhile, delivered an unusual public apology to Russia for possible damage from the spill on the Songhua River, which is flowing toward a city in the Russian Far East.

Beijing’s show of care and contrition was almost unprecedented and represented an effort to restore its damaged standing with both China’s public and Russia, a key diplomatic partner.

The government said benzene levels in the Songhua near Harbin were dropping. But it said running water would not resume until 11 p.m. today, a full day after originally planned when the shutdown occurred because of a chemical plant explosion, setting off panic-buying of bottled water in this city of 3.8 million people.

“We are a people’s government. We should show a high degree of responsibility to the people,” Wen told local and provincial leaders, according to the state television national news. “We cannot allow even a single person not to have water.”

Wen promised to “conscientiously investigate the reasons and responsibility for the accident,” the report said.

Work crews were installing more than 1,000 tons of carbon filters at water plants in preparation for treating water from the Songhua River once it is deemed safe, state media reported today.