An overcrowded bus hit a tanker truck in the southern port city of Karachi, Pakistan, early Sunday, killing scores of people and injuring many others. Both vehicles also caught fire as well.

Although the total number of dead people varied across news reports, a report from Pakistan Today indicated that the actual death toll may be higher. Dr. Seemi Jamali, Karachi's Jinnah Post Graduate Medical Center (JPMC) deputy executive director, described the grisly accident scene.

"We have received more than 57 bodies, but the death toll may rise as most of them are completely burnt and stuck to each other," Jamali said. "They are beyond recognition; they can only be identified by DNA test."

Jamali added that the bodies of six children were stuck to women, noting that it was impossible to separate the remains. Identifying the victims would be a daunting task, according to her.

"Since a blood sample cannot be obtained from these mutilated bodies, we have to collect parts as essential samples," Jamali said.

Pakistan Today reported that rescue workers were busy evacuating bodies and the injured at the crash site. Information Minister Sharjeel Memom of Sindh province elaborated on what the workers found.

"The bus and all passengers were so badly burnt that we have to carry out DNA tests for identification," Memom said.

According to Pakistan Today, the collision occurred at the National Highway when the bus was headed outside of Karachi to Shikarpur. However, officials are still investigating the cause of the accident.

"We are trying to ascertain if the driver of the oil tanker was solely at fault or whether the bus driver also showed negligence," senior police official Rao Mohammad Anwaar said.

Syed Shoaib Hasan of the Wall Street Journal reported that Anwaar thought that the fire came from a gas cylinder on the bus and not from fuel on the truck.

"The accident took place on a single-track road connecting to the main highway," Anwaar said. "It appears to have happened due to a combination of rash driving and poor road conditions."

Rescue workers at the scene told the Wall Street Journal that the intense heat melted some of the metal frame of the bus. In order to retrieve some of the bodies, workers had to cut the vehicle open.

Pakistani police indicated to the Wall Street Journal that eight passengers escaped unharmed, while three were slightly injured.

Karachi resident Gul Hassan told Pakistan Today that he lost nine relatives in the crash, including an 80-year-old head of the family and a two-year-old child. He also noted that two women and another child died in the crash's inferno.

"They were travelling in the same bus," Hassan said of his relatives. "I cannot recognize any of them, all the bodies are completely burnt."

According to Pakistan Today, statistics from the Pakistan Bureau of Statistics indicated that close to 9,000 road accidents are reported to the police every year since 2011, killing an average of over 4,500 people in that country.