ISLAMABAD: Police on Wednesday said that they were investigating how and why a parcel containing anthrax was sent to the prime minister's official residence in the capital Islamabad last month.

It appeared to be the first reported case of anthrax sent to a government office in Pakistan.

“The parcel containing anthrax powder was sent last month, about 20 days ago. After the laboratory test confirmed that the parcel contained anthrax we registered a case against unknown people,” said police officer Hakim Khan.

There was no immediate confirmation from the prime minister's house, which lies in the heavily secured secretariat area of Islamabad.

The parcel was posted from the Jamshuru district in Sindh.

“We have sent a police team to investigate it and to find the culprits there,” said Khan, a police officer in the secretariat district.