Afghan officials say the Taleban has killed one of the 23 South Koreans it kidnapped last week in southeastern Afghanistan.
An Afghan police official says militants shot the Korean because the hostage was sick and could not walk.
Earlier, a purported Taleban spokesman, Qari Yousuf Ahmadi said the militants had killed one of the five men in the group, which also includes 18 women.
South Korea has not confirmed the killing.
The Taleban says it will kill the remaining hostages by 1 a.m. local time Thursday if Afghan authorities do not release Taleban prisoners.
The militant group says it has lost patience after several days of negotiations with tribal elders representing Afghan and South Korean officials.
The head of the Afghan negotiating team, Waheedullah Mujadadi says the Taleban tried to kidnap him today, but he managed to escape.