Islamabad, Nov 28 (IANS): Pakistan terror group Jundullah Friday claimed responsibility for Wednesday's attack on polio workers which claimed the lives of four people, including three women health workers, in Quetta, Dawn online reported.

Four immunisation workers were killed and three others were injured Wednesday morning when armed men opened fire on a polio vaccination team near Quetta's Eastern Bypass area.

The vaccination campaign had been launched amid tight security in 11 districts of Balochistan earlier this month.

During the campaign, over 238,000 children below the age of five were to be administered the vaccine.

At least 10 cases of polio have so far been reported from Quetta, Killa Abdullah and Zhob districts of Balochistan this year.

Militant groups often attack polio teams as they see vaccination campaigns as a cover for espionage.

There are also long running rumours about polio drops causing infertility.