The kidnapping of 23 South Korean aid workers last week on one of Afghanistan's major highways is the latest evidence that the Taliban is extending its reach closer to the capital, Kabul.

The insurgency, which has blossomed in provinces bordering Pakistan – where the Taliban is widely believed to receive support – is spreading inland.

The bus load of South Korean aid workers was taken in Ghazni Province, which has no border with Pakistan yet has become the "kidnapping capital of the country," according to Nic Lee, director of the Afghanistan NGO Safety Office (ANSO) in Kabul. By his count, 60 people have been kidnapped in the southern province since April 1.

Also last week, two German aid workers were kidnapped in Wardak Province, which borders Ghazni and is even further removed from Pakistan. One has died, though the circumstances of his death remain disputed.

It suggests that the Taliban have consolidated enough power in border provinces to strike farther north, with an eye toward ringing Kabul from the south. Few analysts say that Kabul itself is in danger of direct attack, and none say it is in any danger of falling. But the situation echoes what happened to the Soviets two decades ago, when they maintained control of the cities and little else.

"Ghazni is important as the gateway to Kabul, and control of that road is very important, both symbolically and practically," says Joanna Nathan, a Kabul-based security analyst for the International Crisis Group.

The Taliban had set a deadline of 7 p.m. local time (10:30 a.m. Eastern time) Monday for authorities to meet their demands – the swap of Taliban prisoners for hostages. On Monday, the deadline was extended by 24 hours. The Afghan National Army says it has surrounded the area where the hostages are being held and is ready to act. But South Korean negotiators, who have flown into the country, and Afghan elders are pressing hard for a peaceful settlement.

Their task has been made more difficult by the precedent set by the release of Italian journalist Daniele Mastrogiacomo, experts say. He was kidnapped earlier this year, then set free in exchange for several high-ranking Taliban hostages.

In Wardak, one of the two Germans kidnapped last week has been confirmed dead. The Taliban says it executed both men Saturday; German officials say one remains alive and the other died from the stress of his detainment.

The German government has refused to bow to the captors' demands: the removal of its 3,000 troops from Afghanistan. South Korea, however, has banned any citizen from traveling to Afghanistan, with penalties that reach as high as one year in jail or a $3,200 fine. It had already decided to withdraw its troops by year-end, even before the kidnapping. South Korea, according to the Associated Press, has 210 troops (including 150 in a medical unit) that have been stationed at the US Bagram air base since 2002.

Experts agree that the Korean aid workers (18 women and five men who are members of an evangelical Christian church doing medical and education work) made several key errors in judgment. It is widely known that the highway they were traveling is not secure for foreigners. Yet despite their obviousness as foreigners, they chartered a private bus for the seven-hour trip to Kandahar, in the heart of the insurgency.

Despite the increased attention on kidnapping in Afghanistan, those who are caught remain those who make basic mistakes, says Mr. Lee of ANSO: "They make really poor security decisions."

The Ghazni seizure is believed to be the largest single kidnapping in Afghanistan following the fall of the Taliban in 2001. Yet it falls into the same pattern of other kidnappings here, which focus largely on targeting anyone seen to be working on behalf of the Western-backed government – be they aid workers, security personnel, or politicians. There appears to be no obvious trend beyond that, Lee says: No one group – foreign or local – seems to be targeted more than another.

The increasing instability on Kabul's southern doorstep is a concern for President Hamid Karzai's government and its allies. The insurgency has always been centered in the south, where the Taliban was born from ultraconservative Pashtun tribes. But it is creeping northward and farther from Pakistan.

"It is getting farther away from the border," says Ms. Nathan. "What was cross-border is becoming local."

In recent months, suicide bombings in the far north – in Badakhshan and Kunduz – also suggest an attempt to widen the theater of combat, at least superficially. The attempt is more deeply rooted in Ghazni, where the Taliban can attempt to marshal support from a disaffected local populace made up largely of conservative farmers. Local Taliban have been reinforced by Taliban from the deeper south, says Lee.

This does not necessarily suggest growing sympathy for militant Islam. Rather it indicates that some Afghans have lost their patience with the government and are turning against it. The effect has been to constrict the flow of trade on roads south of Kabul, cutting it off from a major trading partner, Pakistan.

"I don't think there is any plan to assault Kabul; they just need to isolate it," says Lee. "Attacking a main supply route in a war is just what happens."