Updated

More than 1,000 people shouted anti-Taliban slogans in eastern Afghanistan on Friday, protesting the slayings this week of 26 young men from their community by militants in the south.

The unprecedented demonstration in the eastern Laghman province was one of the largest anti-Taliban gatherings since the fall of the hard-line Islamist regime following the U.S. invasion in late 2001.

On Sunday, Taliban stopped a bus in southern Kandahar province's Maiwand district, a militant-controlled area, and killed 26 of the passengers — beheading at least six of them. A Taliban spokesman said the men were targeted because they were members of Afghan security forces.

But Afghan officials disputed that any soldiers were on the bus, saying the Taliban insurgents had killed innocent civilians who were on their way to find jobs in neighboring Iran.

Hundreds of thousands of Afghans cross illegally into Iran every year, seeking jobs and refuge.

Protesters from Laghman's Alingar district — where most of those killed came from — shouted "Death to Taliban" and "Death to killers" in the provincial capital of Mehtar Lam. They waved black flags in a sign of mourning.

"They were innocent people, trying to find jobs, and they killed them," Abdul Wakil Attock, the spokesman for the provincial governor, said about the victims.

The protest in Laghman, a province next to Kabul, underscores the growing rivalry among Pashtuns, the dominant ethnic group in Afghanistan that also form the core of the Taliban fighters.

An anti-Taliban protest by Pashtuns, like Friday's, will likely provide the U.S. and other international forces with an opportunity to exploit the rift to drive a wedge between the insurgent group and the civilian population.

Separately, a U.S. coalition raid in Paktika killed three insurgents and detained four others Thursday, the coalition said in a statement.

The troops were targeting an insurgent leader accused of facilitating the movement of foreign fighters and weapons throughout eastern Afghanistan.

The region borders Pakistan's lawless tribal belt, which the U.S. says militants use as a sanctuary from which to launch attacks in both countries.

There has been a spike in violence in Afghanistan this year. More than 5,200 people — mostly militants — have died in insurgency-related violence, according to figures provided by Afghan and Western officials.