KARACHI, Pakistan — Fires at two clothing factories in Pakistan left 283 people dead — many trapped behind locked doors and barred windows — tragedies that highlight workplace perils in a country where many buildings lack basic safety equipment and owners often bribe officials to ignore the violations.

The blazes broke out Tuesday night at a garment factory in the southern port city of Karachi and a shoe manufacturer in the eastern city of Lahore. At least 258 people died in the fire in Karachi, where rescue workers were still searching Wednesday for bodies in the charred building. Another 25 perished in Lahore.

Panicked workers in Karachi had only one way out since the factory’s owner had locked all the other exit doors in response to a recent theft, officials said. Many victims suffocated in the smoke-filled basement.

“The owner of the factory should also be burned to death the way our dear ones have died in a miserable condition,” said Nizam-ud-Din, whose nephew was killed in the fire, one of the deadliest industrial accidents in Pakistani history.

Police were searching for the factory’s managers and placed the owner on a list of people who are not allowed to leave the country, said Roshan Ali Sheikh, a top government official in Karachi.

“It is a criminal act to lock the emergency exit doors, and we are trying to know who did it, and why,” Sheikh said.

The fire started when a boiler exploded and the flames ignited chemicals that were stored in the factory, which manufactured jeans and other clothes for export. Between 300 and 400 workers were inside when the blaze erupted.

Many of the deaths were caused by suffocation as people trapped in the basement were unable to escape when it filled with smoke, said Karachi fire chief Ehtisham-ud-Din.

Those on the upper floors of the five-story building had to break through metal bars covering the windows so they could leap to safety. Dozens were injured doing so, including a 27-year-old pregnant woman.

“When smoke spread all around, I jumped out the window in panic,” said Mohammad Shahzad, who broke an arm and a leg when he hit the ground. “I found myself in the hospital when I regained my senses.”

Others burned to death as they tried to wriggle through the barred windows.

“There were no safety measures taken in the building design,” said senior police official Amir Farooqi. “There was no emergency exit. These people were trapped.”

Firefighters were still battling the blaze Wednesday. The death toll spiked as they entered previously inaccessible parts of the factory and found scores more bodies. The death toll stood at 258 by Wednesday evening, including a 10-year-old boy, said Sheikh. Another 31 people were injured.

Rani Bibi said her two sons-in-law called Tuesday night to say they were trapped in the factory and asked her to tell their wives to take good care of their children. She hasn’t heard from them since, and couldn’t find their bodies in any of the hospitals in the city.

“We don’t know where they are,” said Bibi, tears flowing down her face. “I hope to hear their voices. My two daughters’ lives are ruined.”

The fire that swept through the four-story shoe factory in Lahore left 25 people dead, some from burns and others from suffocation, said senior police officer Multan Khan.

The fire broke out as workers were trying to start a generator after electricity went out in the building. Sparks from the generator made contact with chemicals used to make shoes, igniting the blaze, which blocked the only exit. Firefighters had to break through the building’s brick walls to save people, officials said.

Raza Rumi, an analyst at the Islamabad-based Jinnah Institute, said the fire in Karachi was one of the deadliest industrial accidents in the country’s history.

“It is reflective of the utter collapse of regulation and the enforcement of labor laws in the country,” he said.

The problem has gotten worse in recent years as the federal government handed over factory oversight to provincial authorities, but local governments failed to develop legislation enforcing labor laws or basic safety regulations, Rumi said. Many Pakistani factories lack even basic safety equipment, such as alarms and sprinklers.

In Punjab province, where Lahore is the capital, authorities abolished labor inspections altogether in 2003 to develop a more “business-friendly environment,” Rumi said.

It was unclear whether anger over the fires in Karachi and Lahore will prompt provincial governments to focus on passing new labor regulations.