Taliban insurgents will release all 19 South Korean Christian volunteers they have held hostage in Afghanistan since mid-July, South Korea's presidential Blue House said on Tuesday.

The Taliban agreed to the release after South Korea agreed to meet certain conditions such as halting its citizens from conducting Christian missionary activity in Afghanistan.

A presidential spokesman said it may take some time before the actual release.

The Taliban Islamic movement seized 23 Korean Christian volunteers on July 19 from a bus in Ghazni province. It killed two male hostages after a series of deadlines but freed two female captives as a gesture of goodwill during a first round of talks.