Donations made by the British public to help victims of the worst floods in Pakistan's history have reached £6 million, UK charities said today.
The Disasters Emergency Committee (DEC) said around 545,000 survivors have been provided with emergency care, clean water, food or shelter as a result of British aid.
An estimated 15 million people have been affected by heavy monsoon rains, with money continuing to be donated to help those caught up in the aftermath.
Flooding has reached Sindh province, in southern Pakistan, with reports stating the protective bund at Torhi in the province's north was breached, and several dams were under threat from floodwater.
The United Nations earlier warned Pakistan would need billions of dollars to recover from the devastation, further straining a country already dependent on foreign aid to prop up its economy and back its war against Islamist militants.
Approximately 1,600 lives have, so far, been claimed following heavy rains in the worst-hit north west part of the country.
Almost four million people have been affected in this region, including 1.5 million who were made homeless, the DEC said.
DEC chief executive Brendan Gormley said: "With further monsoon rains expected over the next few days, it is clear that the situation for millions of people in Pakistan is going to get worse before it gets better.
"We are very concerned about reports that the Swat Valley has been cut off by mudslides which will hamper the relief effort.
"We still need people to keep giving because the flood waters are still spreading fast affecting millions of people.
"DEC member agencies and their partners have already reached over 500,000 people on the ground but with roads and bridges washed away and landslides blocking access to some areas the challenges we face are considerable. We urgently need the public's help to save more lives."
Clean drinking water was an immediate priority following reports of cholera in the Swat Valley and the risk from water-borne diseases and infections.
The Department for International Development said yesterday that it had called in the Royal Air Force to help distribute aid including tents for thousands of refugees.