KABUL- The Taliban have freed most of the 27 prisoners captured last week in Afghanistan's northern Badakhanshan province, a local official said today, but three remained captive because of their senior rank.

The prisoners, most of them police officers, were taken in a battle for Yamgan district, after several days of fighting.

"They still hold the prison chief, police chief and a NDS (intelligence agency) agent," district Governor Nawroz Mohammad Haidari said by telephone.

Yamgan initially appeared to have fallen to the Taliban, but local officials say it has since been recaptured by Afghan security forces.

Violence has intensified since the Taliban launched the start of the summer fighting season on May 12 in advance of the planned withdrawal of most foreign troops by the end of the year.

The country's presidential election to replace Hamid Karzai, who cannot run for a third term, is underway, with a run-off round between the two top finishers set for June 14.