PESHAWAR, Pakistan — A Pakistani health official says a five-day anti-polio drive has been launched in the country to vaccinate millions of children under five years of age against the crippling disease.

Aimal Khan, a spokesman with the anti-polio drive, says the campaign was launched on Monday amid tight security.

He says a total of 23.8 million children are to be vaccinated in the campaign, which involves a total of 161,000 health workers in 109 districts.

Pakistan is one of few countries where polio is still endemic, along with Afghanistan and Nigeria. After constant efforts for years, Pakistan is close to completely eradicating the disease.

Pakistan's government regularly launches anti-polio drives despite threats from the Taliban, who perceive the campaign as part of a Western conspiracy and claim it will sterilize Pakistani children.