Pakistani volunteers move a health worker wounded in an attack on an anti-polio team in Balochistan on November 26, 2014.

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Attackers open fire on polio vaccination team in eastern Quetta, police say

Two polio workers die in attack, two others die later at the hospital

There was no immediate claim of responsibility

Official: "We will not bow down before terrorists"

Quetta, Pakistan CNN —  

Four members of a polio vaccination team were killed by militants Wednesday in western Pakistan’s Balochistan province, police said.

Attackers on two motorcycles opened fire at the team in the eastern part of Quetta, the capital of Balochistan province. Two polio workers were killed during the attack, and two others who were injured died later at a hospital, said Imran Qureshi, a senior police officer.

There was no immediate claim of responsibility.

The province’s chief minister, Malik Baloch, vowed to protect polio vaccination teams and bring the attackers to justice.

“We will not bow down before terrorists,” Baloch said.

Militants have targeted anti-polio campaigns in Pakistan since U.S. intelligence officials used a vaccination program to help in their hunt for Osama bin Laden in 2011. Under cover of the program, the CIA sought to collect DNA samples from relatives of the al Qaeda leader to verify his presence in a compound in Abbottabad, Pakistan.

CIA policy: Won’t use vaccination programs as part of operations

Balochistan’s government launched a polio vaccination campaign after a rise in polio cases. Fourteen polio cases have been reported this year in the province.