Water is flowing again in the western part of the Syrian city of Aleppo, but a water pumping station in the east remains damaged, according to Unicef.
That means hundreds of thousands of people in the rebel-held east of the city continue to be without clean water.
Earlier the UN agency had warned the lack of running water in the city had put people at risk of "catastrophic outbreaks" of waterborne diseases.
Syrian government and rebel forces battled for control of high ground on the Aleppo outskirts on Saturday as warplanes relentlessly bombed the city's east as part of a Russian-backed offensive.
- Video report by ITV News Reporter Marc Mallett:
Heavy air strikes on Saturday morning hit at least four areas of the opposition-held east, killing 54 by lunchtime, according to rebels.
The attacks on Saturday follow the deaths of 91 people in the east in the second day of intense bombings described by an expert as "nothing short of Armageddon".
A spokesman for Ban Ki-moon said the UN secretary general was "appalled by the chilling military escalation" in Aleppo.
Meanwhile, speaking at the UN, Syria's foreign minister Walid al-Moualem said they Syrian army was "making great strides in its war against terrorism, with the support of the true friends of the Syrian people, notably the Russian Federation, Iran and the Lebanese national resistance".