Afghan authorities on Tuesday recovered the body of a second South Korean shot dead by Taliban kidnappers who threatened to kill more of the 21 hostages if Kabul does not free rebel prisoners by 0730 GMT (0230 EST) on Wednesday.
The blood-stained body of the bespectacled male Korean was dumped on a clover field beside a road in Arzoo, a village lying some 10 km (6 miles) to the southeast of the town of Ghazni.
"If the Kabul administration and Korean government do not give a positive reply to our demand about the release of Taliban prisoners by tomorrow 1200 (local time), then we will start killing other hostages," Taliban spokesman Qari Mohammad Yousuf told Reuters by telephone from an unknown location.
He said Afghan negotiators had not contacted the Taliban since the second hostage was killed on Monday evening and said the insurgents suspected the Afghan government and foreign troops were intending to launch a rescue bid.
Any attempt to rescue the hostages by force would put the Korean's lives at risk, he warned.
The victim was identified as Shim Sung-min, 29, a former employee of an IT firm who did volunteer work to help the poor.
Police cordoned off the site in the village of Arzoo where his body was found fearing it could have been booby trapped, but managed to recover it later.
The village is some 80 km (50 miles) from where the group of 18 women and five men were seized near Qarabagh on the main highway south from Kabul, undermining statements by Afghan officials who said government forces had the kidnappers surrounded.
The hostage crisis has focused attention on growing lawlessness in Afghanistan with Taliban influence, undermining foreign support for the government.
Suicide bombings and attacks have spread to many areas previously considered safe, making road travel between major cities a risky affair and undermining support for the government in Kabul. Ordinary Afghans weigh the brutality of the attacks against claims of civilian deaths from coalition airstrikes.
Shim's mother cried hysterically when she arrived at the Saemmul Church in suburban Seoul after hearing the victim may have been her son. "Why did you kill him? Please save his life," Shim's mother said through her tears.
Shim's father, a provincial assembly member, described his son as a gentle soul. "He had a good heart and did a lot of volunteer work. My son also wanted to help the poor and disabled," Shim Chin-pyo told reporters.
The Taliban shot Shim after other deadlines they set for the release of rebel prisoners expired.
Negotiations had reached a deadlock with Afghan authorities demanding the release of the 18 women before any prisoners were freed and the kidnappers insisting its fighters should be let out of jail first, according to a Western security analyst.
Taliban spokesman Yousuf said Shim was killed because Afghan authorities were ignoring their demands.
On Wednesday, the Taliban killed the leader of the group.
Al -Jazeera television broadcast a video showing at least seven of the female hostages, wearing headscarves and apparently unharmed. Four were sitting on the ground, the rest standing beside men in Afghan robes, apparently militants.
The television said an off-camera speaker was reading a statement but it did not report what he said
The abduction of the Koreans came a day after the Taliban seized two German aid workers and five Afghans in neighboring Wardak province.
The body of one of Germans has been found with bullet wounds, but the other German along with four Afghans are still held by the Taliban who want Germany to pull out from Afghanistan. One of the Afghan captives managed to escape.