The situation in Sindh "is getting from bad to worse," Giuliano said. "We are delivering [aid] faster and faster, but the floods seemed determined to outrun our response."
Sindh is also home to historic tombs, graves and other remnants of the Mughal Empire, which during the height of its power in the 18th century ruled almost all of what is now India and Pakistan.
One new estimate suggests around 200,000 livestock animals, crucial to the agricultural communities in the southern flatland, have died in Sindh province alone, according to Al Jazeera's Imran Khan, reporting from Shikarpur.
Almost 17.2 million people have been significantly affected by the floods, the United Nations has said, and around 1,600 dead have been counted thus far.
People 'on the move'
"The crisis here is only growing," Al Jazeera correspondent Zeina Khodr, reporting from Hyderabad, said on Friday.
|The flooding, indicated in yellow, is expected to spread south with the Indus River [Al Jazeera]
"The floodwaters [are] trying to make their way to the Arabian Sea. Instead, they are breaching embankments and inundating a number of villages."
Government officials said flooding has submerged 40 per cent of Thatta district, the southernmost part of Sindh, Khodr said.
Residents along the Indus "are on the move, carrying whatever they can," she said.
Those with some mode of transportation are heading to the port city of Karachi, those without are going to Hyderabad.
Government officials have extended evacuation orders to include the city of Shahdadkot, home to some 100,000 people.
On Thursday, authorities ordered residents to evacuate the threatened towns of Sujawal, Mirpur Bathoro and Daro after the swollen Indus breached an embankment near the village of Surjani. Some 400,000 people are believed to live in those towns.
The floods have already washed away at least 40 villages in Sindh and are not expected to recede for months.
Taliban threat remains
Azam Tariq, a spokesman for the Pakistani Taliban, hinted on Thursday that the group might follow through on plans to attack foreign aid workers that the United States government had earlier warned about, the Associated Press (AP) reported.
PJ Crowley, the US state department spokesman, told reporters on Thursday that the government has "information of the potential targeting of foreign
relief workers in Pakistan, as well as government ministries".
Tariq told the AP that the Taliban believed relief workers had hidden motives.
"Behind the scenes [the aid workers] have certain intentions, but on the face they are talking of relief and help," he told the AP by telephone from an undisclosed location.
"No relief is reaching the affected people, and when the victims are not receiving help, then this horde of foreigners is not acceptable to us at all".