Islamabad, Pakistan (CNN) -- At least 100 people died after taking what officials suspect may have been tainted heart medicine in the eastern Pakistani city of Lahore, the health ministry said Thursday.
The government of Punjab province has sealed the pharmaceutical factory believed to have manufactured the medicine.
"The medicine may be contaminated with some heavy metal which created an adverse drug reaction," said Dr. Javed Akram, the doctor leading the investigation into the deaths.
The medication was provided free of charge by the government-run Institute of Cardiology.
Akram said the patients taking the medicines were brought to hospitals with symptoms of a sudden drop in white blood cell and platelet levels, and bleeding from different body parts.