The Afghan government is "under extreme pressure, and they are embarrassed, so we want to keep them in this situation and sustain this crisis for a while," the militant said in a phone interview.
He did not say exactly how the group planned to draw-out the situation, but he did say the killing "might stop," if only temporarily. The commander spoke to CBS News on condition that he not be named.
Mullah Sabir Nasir, the senior Taliban commander in Ghazni province, where the South Koreans were abducted more than two weeks ago, told CBS News that two hostages were killed due to the Afghan government "cheating us" in negotiations for their release.
Nasir, who holds one of about 30 seats on the Taliban's "supreme council" of leaders, said government negotiators had repeatedly gone back on promises to release Taliban prisoners in exchange for the hostages' — 21 of whom are still said to be alive.
He expressed frustration at apparently not being able to negotiate directly with South Korean officials, suggesting the government of Afghan president Hamid Karzai was blocking any such discussion.
"The Afghan government just wants to make us angry, and push us to kill all the hostages at once to bring an end to the crisis," Nasir told CBS News.
The senior Taliban commander who spoke anonymously to CBS News said the militants were considering the release of the female hostages.
He stressed that if the 18 women were freed, "there will be no money". In recent interviews with CBS News, Taliban leaders have repeatedly denied reports that any ransom was being sought.
The second slain hostage's body, a man, dressed in Western clothing and with glasses, was found on the side of the road at daybreak Tuesday in the village of Arizo Kalley in Andar District, some 5 miles west of Ghazni city, said Abdul Rahim Deciwal, the chief administrator in the area.
The South Korean Foreign Ministry identified the victim as 29-year Shim Sung-min, a former information technology worker who volunteered with a South Korean church group on an aid mission to Afghanistan.
"The Kabul and Korean governments are lying and cheating. They did not meet their promise of releasing Taliban prisoners," a purported Taliban spokesman said earlier by phone from an undisclosed location.
The Afghan government said releasing militant prisoners was not an option.
"We are not going to discuss the details, releasing or not releasing of criminals in exchange for the hostages," said Humayun Hamidzada, spokesman for President Hamid Karzai. "We are doing everything we can to secure their release."
In March, Karzai approved a deal that saw five captive Taliban fighters freed for the release of Italian reporter Daniele Mastrogiacomo. Karzai, who was criticized by Washington and European capitals over the exchange, called the trade a one-time deal.
"As far as the comparison with the Italian hostage situation is concerned, I don't think that this should become an industry in Afghanistan," Hamidzada told a news conference Tuesday. "I don't think anyone supports it ... as a principle, we shouldn't encourage kidnapping by accepting their demands."
In South Korea, the dead man's father, Shim Jin-pyo, said his wife collapsed when the family heard their son was the Taliban's latest victim.
Appearing calm and soft-spoken, Shim Jin-Pyo said he wondered how the Taliban "could perpetrate this horrible thing."
The relatives of the hostages appealed for support from the United States and the international community to resolve the hostage standoff.
"In particular, the families want the United States to disregard political interests and give more active support to save the 21 innocent lives," said Kim Jung-ja, mother of Lee Sun-young, one of the remaining captives.
Earlier, the Al-Jazeera television network showed shaky footage of what it said were several South Korean hostages. It did not say how it obtained the video. The authenticity of the video could not immediately be verified.
Some seven female hostages, heads veiled in accordance with the Islamic law enforced by the Taliban, were seen crouching in the dark, eyes closed or staring at the ground, expressionless.
The hostages did not speak as they were filmed by the hand-held camera.
The Taliban kidnapped 23 South Koreans riding on a bus through Ghazni province on the Kabul-Kandahar highway on July 19, the largest group of foreign hostages taken in Afghanistan since the 2001 U.S.-led invasion.
The Taliban has set nearly a dozen deadlines for the South Korean lives. Last Wednesday the insurgents killed their first hostage, a male leader of the group.
The body of pastor Bae Hyung-kyu arrived back in South Korea on Monday.
On Sunday, Karzai and other Afghan officials tried to shame the Taliban into releasing the female captives by appealing to a tradition of cultural hospitality and chivalry. They called the kidnapping of women "un-Islamic."