Islamabad: As many as eight people were killed and four others injured when an oxygen cylinder exploded inside an ambulance in Pakistan's southern Sindh province on Wednesday night, police said.

The explosion occurred in an ambulance in Nagarparkar city of Tharparkar district, according to police.

The injured were shifted to Karachi after receiving initial medical treatment, while the bodies were transferred to a local hospital for identification, officials said, Xinhua News Agency reported.

The ambulance was parked at a health facility at the time of the explosion, according to local media.

Police said specialist teams from Mirpurkhas and Karachi had been called in to examine the evidence and determine the cause of the explosion.

In a separate incident, at least two people lost their lives, and five others sustained critical injuries on Wednesday following a massive explosion caused by a gas bowser colliding with another heavy vehicle in southern Pakistan's Sindh province, local police officials confirmed.

The incident occurred along the National Highway near the busy Rohri Interchange, situated within the Sukkur district of Sindh. According to preliminary reports from the responding police authorities, the disaster unfolded when a high-capacity gas bowser carrying volatile fuel collided at high speed with another heavy trailer travelling along the arterial route.

The impact of the collision ruptured the bowser’s pressurised tank, triggering a violent blast and a subsequent firestorm that engulfed surrounding transport vehicles.

Police confirmed that both individuals killed in the tragedy were occupants of the gas bowser, specifically the driver and the vehicle's cleaner, who were caught directly in the immediate blast radius and died on the spot.

Emergency services and rescue teams rushed to the crash site shortly after receiving reports of the explosion. The five injured victims, many of whom suffered severe burns and trauma injuries, were evacuated from the wreckage and transferred to a nearby medical facility in Sukkur for urgent treatment. Medical personnel reported that several of the injured remain in critical condition.

The force of the blast and the resulting inferno caused extensive destruction to surrounding vehicular traffic along the highway. Authorities noted that a total of six additional vehicles were damaged or destroyed in the blast, including two fuel tankers, three heavy cargo trailers, and a commercial Mazda truck.