KARACHI (AFP) - Pakistani police said they arrested five alleged Taleban suspects on Wednesday on suspicion of killing women polio vaccinators and plotting to attack Karachi airport.

"We have arrested five men from Ittehad Town in Karachi's west today who were involved in killing four out of five female health workers in Karachi last month," senior police official Ghulam Shabbir Shaikh told reporters.

Gunmen in Pakistan last month killed nine health workers carrying out polio vaccinations, five of them in Karachi in attacks that prompted UN agencies to suspend work on a nationwide inoculation campaign.

"They belong to Tehreek-e-Taleban Pakistan (TTP) and were planning to hit Karachi airport and other high-profile establishments to create panic and chaos," he added, referring to the country's umbrella Taleban organisation.

There was no claim of responsibility for December's killings, but the TTP last year banned polio vaccinations in the northwestern tribal region of Waziristan, condemning the campaign as a cover for espionage.

Pakistan is one of only three countries in the world where polio is endemic, but rumours about the vaccine being a plot to sterilise Muslims have long dogged efforts to tackle the highly infectious disease.

Polio cases in Pakistan hit 198 in 2011 - the highest figure for more than a decade and the most of any country in the world, according to the World Health Organisation.

Karachi is Pakistan's largest city with an estimated population of 18 million. Its Arabian Sea port is used by the United States and Nato to ship supplies to the war in neighbouring, landlocked Afghanistan.

The TTP, blamed for the majority of suicide attacks and assassinations in Pakistan, have been fighting a domestic insurgency since 2007.