QUETTA: A spokesman for the proscribed militant group Jundullah on Friday claimed responsibility for Wednesday's attack on polio workers which had claimed the lives of four people, including three Lady Health Workers (LHW), in Quetta.

A spokesman for the banned outfit called media representatives and claimed the responsibility for killing the polio workers in Quetta.

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

Read: Polio workers boycott campaign in Balochistan as 4 workers gunned down

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. The districts where the campaign was launched included Quetta, Killa Saifullah, Killa Abdullah, Sherani, Zhob, Pishin, Loralai, Naseerabad, Jaffarabad and Lasbela.

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.

Balochistan had been polio free for nearly over two years. However, the first polio case was reported from the province's Killa Abdullah district in July this year.

Refusal on the part of parents has been identified as the underlying factor behind increasing cases of polio in the province.