Islamabad: At least four polio workers, including three women, were killed today in an attack by militants in Pakistan's restive southwestern Balochistan Province.
The workers were going from their homes to a health centre when they were attacked near Eastern Bypass area of Quetta city.
They were without any security cover at the time of the attack, Geo TV reported.
Three women and one man died in the attack, while two other women were injured, the report said. Police has confirmed the attack.
A polio vaccination campaign was launched amid tight security in 11 districts of Balochistan earlier this month.
Balochistan home secretary Akbar Durrani has halted the polio campaign in the province.
No group has taken responsibility of the attack yet.
Pakistan government has come under criticism for doing little to eradicate the virus which is a threat to the world.
Security is the main reason for the spread of polio virus as vaccination cannot be organised in tribal areas where Taliban still control large areas.
They consider polio medicine as a conspiracy by the West to sterile Muslims. Peshawar is considered as hub of poliovirus.
Polio is still endemic in Pakistan, Afghanistan and Nigeria. The World Health Organisation in May imposed travel restriction on Pakistan.
Pakistan has already broken its 14-year record of 199 polio cases in one year recorded in 2000.