The hostages are said to be physically well

Seven Christian volunteer charity workers remained in the hands of the militant group after 12 of their colleagues were freed on Wednesday.

The releases came a day after the South Korean government said it had reached a deal with the Taleban.

Two male hostages were killed and two women freed during the kidnap ordeal.

Wednesday's releases were co-ordinated with the help of Afghan tribal elders.

The 12 hostages - 10 women and two men - were freed in groups at separate locations around Ghazni province, several hours apart.

Red Cross officials who helped drive them to safety on Wednesday said the group were "relieved" and physically in good shape.

Troop withdrawal

"We anticipate that the remaining seven will be released this afternoon," presidential spokesman Cheon Ho-sun told a news briefing on Thursday.

He said that, once freed, the group would have medical check-ups at South Korea's army base north of Kabul before flying on to Dubai for a connecting flight home.

In pictures: Hostage release S Korea press wary over deal

Wednesday's releases came a day after the South Korean government held a new round of direct talks with the Taleban.

South Korea agreed to withdraw its 200 troops from Afghanistan as scheduled by the end of the year. It also said it would end all missionary work in the country and stop its citizens from travelling there.

The militants kidnapped 23 South Koreans on 19 July as they travelled by bus on the main Kandahar to Kabul highway.

They subsequently killed two male hostages and later freed two women following a first round of talks.

The hostages are thought to have been held in several different locations in Ghazni province.