Authorities in Pakistan's southern port city of Karachi say at least 14 people have been killed by an apparent toxic gas leak.
Officials said hundreds of others have been hospitalized with breathing difficulties and burning eyes following the deadly incident, which began on February 16 in the coastal neighborhood of Kamari.
"Most of the patients were suffering from choking and breathlessness," Pakistani emergency services official Seemin Jamali said.
Local authorities said residents of Kamari began falling sick and rushing to hospitals on the night of February 16.
The Associated Press quotes hospital officials who said on February 18 that they had treated about 650 people.
Authorities said an evacuation of Kamari residents was planned for February 18 and that they would be taken to safer areas.
The cause of the leak remains uncertain, but officials said there was no evidence of sabotage.
"We are still clueless to find out the possible cause of the incident," Karachi police chief Ghulam Nabi Memon told Pakistan's Dawn newspaper on February 17.
One official noted that a ship at the port was offloading soybeans or a similar cargo at the time, which could have been the cause toxic gas leak.
Nasir Shah, the provincial information minister, said local officials have sought assistance from the navy's chemical and biological department to help determine the source of the leak.
Karachi is Pakistan's largest city, with numerous oil refineries situated nearby, along with a key naval installation.