Afghan authorities are struggling to negotiate the release of 22 South Korean hostages held by the Taliban because of the captors' unclear demands.
On Wednesday, after multiple deadlines passed, the 23rd member of the group, a 42-year-old pastor, was shot and killed on his birthday.
A local police chief said the militants have got "problems among themselves" that is stifling the negotiation process.
"One says let's exchange them for my relative, the others say let's release the women and yet another wants a deal for money," said Khwaja Mohammad Sidiqi, a local police chief in Qarabagh.
In an effort to bolster negotiations, a top South Korean envoy will visit Afghanistan Friday to meet with local officials.
Baek Jong-chun, South Korea's chief presidential secretary for security affairs, said in a statement before departing for Afghanistan that the kidnappers "will be held accountable for taking the life of a Korean citizen."
"Harming innocent civilians can never be justified and we will never forgive this kind of inhumane act," he said.
Bae Hyung-kyu, a pastor travelling with the Christian volunteers, was shot and killed Wednesday.
His body was discovered in Ghazni province in central Afghanistan Wednesday with 10 bullet holes to the head, chest and stomach.
He was reportedly killed because he was sick and couldn't walk.
Taliban spokesman Qari Mohammad Yousuf told Reuters Thursday that the remaining hostages were still alive despite the passing of a Wednesday night deadline set by the captors.
"They are safe and alive," said Yousuf.
He said negotiations with the Afghan government have "given us hope for a peaceful settlement of the issue."
The Taliban may now be waiting to see what offer Baek could bring to the table.
The aid workers, including 18 women, were kidnapped last Thursday in Ghazni district while riding on a bus from Kabul to Kandahar on Afghanistan's major highway.
Afghan President Hamid Karzai in March authorized the release of five Taliban prisoners in exchange for a kidnapped Italian journalist, but he called the trade a one-time deal.
The South Korean church the abductees attend said it will suspend at least some of its volunteer work in Afghanistan.
South Korea has about 200 soldiers serving with the 8,000-strong U.S.-led coalition in Afghanistan, largely working on humanitarian projects. They are scheduled to leave Afghanistan at the end of this year.
South Korea has forbidden its citizens from traveling to Afghanistan. The country also asked Afghanistan to block their entry.
With files from The Associated Press
