The Britain-based charity ActionAid says heavy rains are hampering operations to evacuate people in Pakistan caught in the worst floods in 80 years. The death toll has reached 1,500 and an estimated three-million people have been affected.
Airlie Taylor from Britain-based ActionAid says a break in the rains in Pakistan during the past few days had given rescue teams better access to flooded northern provinces.
"They did die down, which enabled the international community to pick up the relief effort somewhat," Taylor said. "However, more rains are forecasted in the next few days and it is anticipated that the flooding will head south into the Sindh Province in the south of the country. So it looks like the situation may well get worse before it gets better."
Much of the relief effort so far has been aimed at the northwest Khyber-Pakhtunkhwa province, which has been swamped by the worst monsoon rain the country has seen in almost a century.
Floodwaters are pouring south into Punjab province, destroying crops and threatening more lives. Aid workers say they fear bloated rivers may overflow into southern Pakistan.
Taylor says some aid groups are present in Sindh Province, home of the country's commercial center, Karachi.
"We would look into responding there if that situation worsens," Taylor added. "But obviously the capacity of the government, as I say, and aid agencies, is already strained so that is not something that we would want to happen obviously."
In Islamabad, Oxfam aid worker Nisar Shah says many roads and bridges have been destroyed.
"The biggest challenge which we are facing at the moment is to reach to those areas which are in the interior, I mean not on the main roadside," said Shah. "There is a huge population inside those areas."
Crops have been destroyed across northwest Pakistan. Relief workers fear the effects on the next harvest and the United Nations has warned of serious food shortages. The World Food Program estimates 1.8 million people will need to be fed in the next month.
Monsoon season in Pakistan normally lasts until mid-September.