Nearly half a million people have been displaced by flooding in eastern Pakistan after days of heavy rain swelled rivers, relief officials said, as they carried out a massive rescue operation.

Three transboundary rivers that cut through Punjab province, which borders India, have swollen to exceptionally high levels, affecting more than 2,300 villages.

Nabeel Javed, the head of the Punjab government’s relief services, said on Saturday that 481,000 people stranded by the floods had been evacuated, along with 405,000 livestock.

Overall, more than 1.5 million people have been affected by the flooding, including in Lahore, the provincial capital and the country’s second-largest city.

“This is the biggest rescue operation in Punjab’s history,” Irfan Ali Khan, the head of the province’s disaster management agency, said at a news conference.

He said more than 800 boats and some 1,300 rescue personnel were involved in evacuating families from affected areas, mostly located in rural areas near the banks of the three rivers.

The latest spell of monsoon flooding since the start of the week has killed 30 people, he said, with hundreds left dead throughout the heavier-than-usual season that began in June.

“No human life is being left unattended. All kinds of rescue efforts are continuing,” Khan said.

More than 500 relief camps have been set up to provide shelter to families and their livestock. In the impoverished town of Shahdara, on the outskirts of Lahore, dozens of families were gathered in a school after fleeing the rising water in their homes.

In mid-August, more than 400 Pakistanis were killed in a matter of days by landslides caused by torrential rain on the other side of the country, in Khyber Pakhtunkhwa, close to Afghanistan and the only province held by the opposition to the federal authorities.

In 2022, unprecedented monsoon floods submerged a third of Pakistan, with the southern province of Sindh being the worst-affected area.