THATTA, Pakistan — Both sides of the main road were crowded with people from Thatta and nearby flooded villages fleeing the floodwaters. Many had spent the night sleeping out in the open.

Hadi Baksh Kalhoro, a Thatta disaster management official, said more than 175,000 people had left the city, leaving few behind.

Some are heading for nearby towns or cities, he said, with thousands also headed for the high ground of an ancient graveyard for Muslim saints.

He said the latest levee breach, which happened early Saturday, could leave the outskirts of Thatta flooded by later in the day. The city is about 125 kilometres southeast of the major coastal city of Karachi.

The floods began in the mountainous northwest about a month ago with the onset of monsoon rains and have moved slowly down the country toward the coast in the south, inundating vast swaths of prime agricultural land and damaging or destroying more than 1 million homes.

More than 8 million people are in need of emergency assistance across the country.

The United Nations, the Pakistani army and a host of local and international relief groups have been rushing aid workers, medicine, food and water to the affected regions, but are unable to reach many people.

On Saturday, flood victims blocked a road in Thatta to protest the shortage of aid, most of which is randomly thrown from trucks into crowds of needy people.

"The people who come here to give us food treat us like beggars. They just throw the food. It is humiliating," said 80-year-old Karima, who uses only one name. She was living in the graveyard with more than two dozen relatives.

The floods also displaced thousands of minority Hindus in southern Sindh province. About 3,000 were living at a centuries-old Hindu temple inside the sprawling graveyard.

"I am also fasting and praying for the flood to recede as it has already snatched husbands from wives, sons and daughters from parents, brothers from sisters, and sisters from brothers," said Geeta Bai, 32, as she sat outside the temple.

Pakistan's population is nearly all Muslim.

The new levee breach came as captured Islamist militants seized their guards' weapons during an interrogation Saturday and took two hostage, setting off a gunbattle, officials said.

Police officials initially said militants had attacked the army intelligence office during the interrogation but later said the assault had not come from outside.

The militants "overpowered two sentries" and took them hostage, said Maj. Gen. Athar Abbas, the Pakistani army spokesman.

Further details remained hazy. The area around the office was sealed off soon after the attack, which began about 6 a.m. Sporadic gunfire could still be heard more than seven hours later.