“It is difficult not to feel deeply moved to hear such detailed descriptions of tragedy,” Mr Guterres said after landing in Sindh, according to a video released by the office of Prime Minister Shehbaz Sharif.
“Pakistan needs massive financial support. This is not a matter of generosity, it is a matter of justice.”
A video released by Information Minister Maryam Aurangzeb showed Mr Guterres seated next to Mr Sharif viewing flood-damaged areas from an aircraft window.
“Unimaginable,” Mr Guterres said while surveying the damage.
Pakistan received 391 millimetres of rain in July and August — nearly 190 per cent more than the 30-year average. Sindh received 466 per cent more rain than the average.
The effect of the torrential rain has been twofold: destructive flash floods in rivers in the mountainous north, and a slow accumulation of water in the southern plains.
Thousands of temporary campsites have mushroomed on slivers of dry land in the south and west — often roads and railway tracks.
With people and livestock cramped together, the camps are ripe for outbreaks of disease, with many cases of mosquito-borne dengue reported, as well as scabies.
“If he comes and sees us, Allah will bless him,” Rozina Solangi, a 30-year-old housewife from a flooded village near Sukkur in Sindh, told AFP on Friday.
“All the children, men and women are roasting in this scorching heat. We have nothing to eat, there is no roof on our heads. So he must do something for us poor.”