An explosion at a ship breaking yard in southwest Pakistan on Tuesday killed at least 11 laborers and wounded dozens of others, police said.

An oil tank exploded while workers were dismantling an old ship, said police official Mohammad Abdullah. Initial reports indicated that dozens of laborers remained trapped after the blast in the coastal town of Gadani, he said. Several other workers jumped overboard into the sea as the fire raged, he added.

Abdullah said rescuers were transporting the casualties to a hospital in Karachi, the capital of southern Sindh province.

Abdul Hakeem Lasi, a rescue worker from Edhi, Pakistan's largest ambulance service, told The Associated Press that so far they had retrieved 11 bodies from the sea. He said they also retrieved several body parts, indicating the death toll was likely to rise, especially as it remained unclear how many people were on the ship at the time of the blast. He said firefighters were struggling to extinguish the blaze.

Shortly after the industrial accident, Pakistani Prime Minister Nawaz Sharif issued a statement expressing sorrow for the "loss of valuable lives." He ordered authorities to expedite the operation to rescue those stranded aboard the burning ship, and urged health officials to provide the best possible care to those wounded.

Gadani is one of the world's largest ship breaking yards and was established in the 1970s. Laborers are often injured while breaking ships there, mainly due to poor safety measures.