Syria's Aleppo reels from new wave of air strikes

Nearly two million civilians are without water in the devastated northern city after regime bombardment damaged a pumping station and rebels shut down another in retaliation, the United Nations said.

Rebel-held districts in east Aleppo came under intense air and artillery fire for a fifth night as the army prepared a ground offensive to recapture the whole of the divided city.

Saturday's death toll of 25 was expected to rise because people remained trapped under rubble, according to the Syrian Observatory for Human Rights, a Britain-based monitoring group.

Seven people were killed in a strike as they queued to buy yoghurt at a market in the Bustan al-Qasr neighbourhood, which sits along the front line that divides the government-held west from the rebel-held east of the city.

On Friday, at least 47 people were killed in heavy bombing, among them seven children, according to the Observatory.

There was massive destruction in several neighbourhoods, including Al-Kalasseh and Bustan al-Qasr, where some streets were almost erased by the bombardment.

The civil defence organisation known as the White Helmets was left overwhelmed by the scale of the destruction, particularly after several of its bases were damaged in bombing on Friday.

In many places, rubble strewn across streets has rendered them impassable and has effectively sealed off neighbourhoods to traffic.

The UN children's agency UNICEF said the loss of mains supply posed serious health risks in rebel-held areas as the only alternative source of drinking water was from highly contaminated wells.

"It is critical for children's survival that all parties to the conflict stop attacks on water infrastructure, provide access to assess and repair damage to Bab al-Nayrab station, and switch the water back on at the Suleiman al-Halabi station," it said.