KABUL, July 31 (Reuters) - The Taliban movement in Afghanistan has set 0730 GMT Wednesday as another deadline for the remaining 21 South Korean hostages, a Taliban spokesman said on Tuesday a day after the Taliban shot dead a second captive. "If the Kabul administration and Korean government do not give a positive reply to our demand about the release of Taliban prisoners by tomorrow 12:00 (local time), then we will start killing other hostages," Qari Mohammad Yousuf told Reuters.