The Taliban said it was losing patience with South Korea officials who have been negotiating for the release of 19 remaining Korean hostages.

“The Korean delegation is telling us again and again that they are discussing the issue with the Afghan government and the U.S. authorities,” said purported Taliban spokesman Zabeehullah Mujahid to The Korea Times on Monday.

But the kidnappers contend that “the Korean side did no[t] seem to be serious about saving the lives of their people” because it was not doing enough to press for an exchange of Taliban prisoners for Korean hostages – the insurgent’s main demand.

For its part, South Korea has made efforts to urge the U.S. and Afghan government to free rebel fighters, such as sending a delegation to Washington to meet with U.S. officials and meeting with Afghan President Hamid Karzai to urge more flexibility.

The Korean delegation has repeatedly explained to Taliban negotiators that it is virtually powerless to release the militant fighters who are held by Afghan and U.S. military.

Both the U.S. and Afghan government have unwaveringly ruled out freeing rebels as an option, arguing that doing so would encourage more kidnapping and terrorism in the already unstable insurgency-wracked country.

“Their (South Korea’s) efforts are not sufficient,” said Mujahid over the phone to Agence France-Presse Monday.

“The Koreans are telling us that ‘we’re trying to persuade the Kabul administration and the U.S. administration and the U.S. government to accept the Taliban demands’ – but it seems they can’t,” he added.

Talks between Taliban and the Korean delegation have been deadlocked since the release of two women hostages last Monday. Though rumors circulated that the two sides were discussing a ransom deal, the Taliban has repeatedly asserted that it is only willing to discuss a prisoner-hostage swap.

It has been over a month since the original group of 23 South Korean volunteers – 16 reportedly females – were abducted in insurgency-plagued Ghazni province. The church group was on its way to provide free medical services to poor Afghan citizens when their bus was hijacked on July 19.

Two male hostages have been killed since the group’s kidnapping – the largest abduction of foreigners in Afghanistan since the fall of the Taliban regime in 2001. The leader of the aid group, Bae Hyung-kyu, was the first victim, found dead July 25 with 10 bullet holes in his body. The body of the second victim, 29-year-old Shim Sung-min, was found July 30.

The Taliban released two hostages Kim Ji-na, 32, and Kim Kyun-ja, 37, last Monday, after it said face-to-face talks with the Korean delegation were going well. It was the first – and so far only – significant breakthrough in the hostage drama that has made headlines around the world.

Elsewhere in Afghanistan, a pregnant German Christian aid worker was rescued from her Afghan captors Monday after 36-hours. Five-months pregnant Christina Meier was kidnapped by a non-Taliban related criminal gang that was motivated by ransom money.

After her dramatic pre-dawn rescue, Meier was flown with her husband to a safe location outside Afghanistan. Medical check-ups prior to her departure showed she was in “perfect health,” according to AFP.