LAHORE - Gunmen shot injured a polio worker and tortured another in two different areas of the provincial metropolis in Lyton Road and Naseerabad police precincts yesterday.

A polio worker Umar Khan was injured when some unidentified armed men opened fire on the polio workers. Umar Khan was shifted to Mayo Hospital. The doctors said his condition was out of danger. District coordination officer said that there was no attack on polio workers. Personal enmity could be a possible reason behind that incident, he was of the view.

Later, DIG Operations Dr Haider Ashraf visited hospital and inquired after the injured man. He said police were investigating the matter and soon the culprits would be behind the bars.

Agencies add: "Initial reports say that two men on a motorcycle opened fire on the vaccinators and ran away," police spokesman Hammad Haider told Reuters.

A health worker was hit by the bullet in his leg and was rushed to hospital, where he was in stable condition on Wednesday afternoon, he said.

He said it was unclear who was behind the shooting.

More than 4,000 vaccinators are working in Lahore alone and each team is assigned two police officers for security, Haider said, adding that the team that was attacked had set out without a police escort.

The attack is latest in a string of attacks against eradication teams in Pakistan that accounts for more than 70 percent of the world's cases of the virus.

More than 100,000 health workers fanned out across Pakistan this week, stepping up a drive to eliminate the polio virus this year from one of its last bastions, despite threats from militants against the vaccination teams.

Polio, which can cause lifelong paralysis, is now endemic in only two countries, Pakistan and Afghanistan.

Pakistan's polio cases are declining, with just 54 cases of polio virus reported last year, down more than 80 percent from 2014, when the country suffered a large spike in cases.

The latest immunisation push aims to finish vaccinating every child in the country by the end of May.

Efforts to eliminate polio in Pakistan have been complicated in recent years, as polio workers have faced attacks by militants who say the health teams are Western spies, or that the vaccines they administer are intended to sterilise children.

In January, a suicide bomber killed at least 15 people outside a polio eradication centre in Quetta, with two militant groups claiming responsibility.