A humanitarian disaster is looming in Iraq's southern city of Basra, the Red Cross has warned.
The Iraqis claim 77 people have been killed in the Basra bombings
Water and electricity supplies to the country's second city have been cut off for more than two days.
Coalition forces have carried out airstrikes on Basra and are holding land positions outside the city.
But British military sources have denied Iraqi claims that 77 people had been killed and more than 300 injured.
The International Committee of the Red Cross (ICRC) said electricity cables powering the Wafa al-Quaid water station had been destroyed.
It claimed the station, which supplies two million people, was under coalition control.
We are aware there may be a number of humanitarian issues there (in Basra) and we're taking measures to try and improve upon them
Lieutenant Colonel Chris Vernon
British forces spokesman
ICRC spokesman Florian Westphal said: "We have not been able to gain access to the main water station today, so we will try and do the same thing tomorrow.
"Sixty per cent of the local population are still without access to a regular water supply - this could develop into a humanitarian crisis.
"We are really, really going to try to gain access to the supply and do anything we can to repair it."
As an emergency measure, the charity's engineers have partially restored the supply by using treated water from nearby rivers.
In response to these concerns, UK Defence Secretary Geoff Hoon has denied the
utilities in Basra were targeted by the coalition.
He told BBC Radio 4's The Westminster
Hour: "I am concerned - and this is being suggested to me now - that it may well be
the Iraqi authorities that are inflicting this harm on their own people -
something we have seen in the past."
The British have taken over the Basra assault
UK military sources confirmed bombing raids were made on Basra on Saturday night, but were mystified by the Iraqi casualty figures.
By Sunday night, the coalition had secured positions on the outskirts of the city, with no immediate plans to enter.
US Marines have withdrawn from the assault, which has been taken over by the British 7th Armoured Brigade, the Desert Rats.
They have been fired on by rocket-propelled grenades, machine guns, artillery and mortars.
Lieutenant Colonel Chris Vernon, British forces spokesman, told BBC News they would advance on the city "when the time was right".
He added: "We are aware there may be a number of humanitarian issues there (in Basra) and we're taking measures to try and improve upon them."
But he said the priority was securing the port of Umm Qasr in order to open up the route for humanitarian purposes and extend water supply lines from Kuwait.
Earlier, the US warned taking control of cities such as Basra will take time.
Lieutenant General John Abizaid, at Central Command in Qatar, said: "You also have to understand that we are not looking to go in and fight house-to-house in these areas."