ISLAMABAD — Investigators scoured the wreckage on Monday of a weekend train derailment that killed at least 34 people, the latest deadly crash to hit Pakistan's antiquated railway network.

More than 1,000 passengers were aboard the Hazara Express when it came off the tracks in a flat, rural part of Sindh Province near Nawabshah, around 250 kilometers by rail from the southern port city of Karachi.

It was winding its way north on a 33-hour journey to Havelian in Khyber Pakhtunkhwa Province when disaster struck near Sarhari around lunchtime.

Muhammad Afzal Kolachi, a spokesman for Pakistan Railways, told Agence France-Presse on Monday the death toll had risen to 34.

Pakistan's Prime Minister Shahbaz Sharif expressed deep grief and sorrow over the incident, and directed the authorities to provide the best medical treatment to the injured people.

Railway minister Khawaja Saad Rafique said on Sunday that no faults had been reported on the stretch of line where the accident happened, but some residents said it had been affected by the monsoon floods that engulfed a third of the country last summer.

"The track is in a bad condition due to last year's floods," said Ali Dost, a 52-year-old local police officer.

Rafique promised a full investigation.

Rescue teams, the Pakistan Army and Pakistan Railways personnel rushed to the site and undertook relief activities. Local volunteers also helped rescue the stranded passengers.

"The down track has been cleared and the work is ongoing on the up track," said Shahnawaz Mashori, a 24-year-old teacher who had volunteered at the site.

"I was sitting in my shop … Suddenly, there was a huge bang," said Azmat Ali, 25, who has a store near the crash site.

"We started running and when we arrived … we pulled out bodies and injured people from the wreckage."

Hospitals in the area declared an emergency as they struggled to deal with dozens of passengers brought in with severe injuries.

After the train derailment, train operations were suspended, affecting the routine of many trains, with railway authorities saying it may take up to 18 hours to restore operations.

Sunday's crash is the latest to hit the network in recent years.

Two trains collided near Daharki in Sindh in June 2021, killing at least 65 people and injuring about 150 others. In that incident, an express derailed onto the opposite track, and a second passenger train plowed into the wreckage a minute later.

At least 75 passengers were burnt to death in a fire aboard the Tezgam express train in October 2019, while a two-train collision at Ghotki killed more than 100 people in 2005.