South Korea's intelligence chief has refused to deny that his government paid a ransom to the Taleban to release 19 hostages last week.

South Korea's embassy in Moscow denied reports that Seoul paid a ransom to Taliban insurgents to secure the release of Korean Christian volunteers in central Afghanistan.

The negotiations that led to the release of 19 South Korean hostages this week by their Taliban captors are being described as a "triumph" for the Taliban by some western politicians and analysts.

Seven South Korean hostages, still being held by Taliban militants in Afghanistan, are expected to be released on Thursday, the Kyodo news agency said, citing a local mediator who has been involved in the negotiations.

Twelve South Koreans have been released by Talibans in three groups throughout wednesday and rest seven is to be released on Thursday.

Taliban militants released eight South Korean hostages on Wednesday, the first of 19 captives scheduled to be freed under a deal struck between the insurgents and the South Korean government.

Taleban representatives say they have agreed to release 19 South Korean hostages held captive in Afghanistan for more than a month. A South Korean presidential spokesman has confirmed that a deal for the release has been reached.

Taliban militants have agreed to release all 19 South Korean hostages being held in Afghanistan, Seoul's Yonhap agency said, citing a spokesman for the South Korean president.

South Korean officials have resumed direct talks with the Taliban in central Afghanistan on 19 Koreans who have been held hostage by the militants for over a month.

Two women among the 23 South Koreans kidnapped by the Taliban in mid-July have been freed on a rural roadside and then driven to a U.S. base, the first significant breakthrough in a hostage drama now more than three weeks old.

South Korean negotiators are today meeting for a second time with Taliban militants who have been holding 21 South Koreans captive for more than three weeks. Today's talks follow a first round on August 10.

A Taliban leader taking part in hostage negotiations for the lives of 21 South Koreans said on Saturday that talks are on a "positive track" and that he hopes the captives could be released "today or tomorrow."