Even by Afghanistan's standards of often-shifting alliances, a meeting between ethnic Hazara elders and commanders of the Taliban insurgents who have persecuted them for years was extraordinary.

The Hazaras - a largely Shiite minority killed in their thousands during the Taliban's hard-line Sunni Islamist rule of the 1990s - came to their old enemies seeking protection against what they deemed an even greater threat: masked men operating in the area calling themselves "Daish", a term for Islamic State in the region.

In a sign of changing times, the Taliban commanders agreed to help, said Abdul Khaliq Yaqubi, one of the elders at the meeting held in the eastern province of Ghazni.

The unusual pact is a window into deepening anxiety in Afghanistan over reports of Islamic State radicals gaining a foothold in a country already weary of more than a decade of war with the Taliban.

Back-to-back kidnappings within a month of two groups of Hazara travelers - by men widely rumored, though far from proven, to claim fealty to IS - have many concerned.

The current threat IS poses in Afghanistan, observers say, is less about real military might than the opportunity for disparate insurgent groups, including defectors from an increasingly fractured Taliban, to band together under this global "brand" that controls parts of Iraq and Syria.

The fear is especially keen among religious minorities who worry the influence of the fiercely anti-Shi'ite IS could introduce a new dimension of sectarian strife to the war.

"Whether Daish exists or not, its psychological impact is dangerous in Ghazni, which is home to all ethnicities," said Mohammad Ali Ahmadi, Ghazni's deputy-governor. "It could easily stir up tensions."

Unlike in Iraq or Syria, IS controls no Afghan territory, and operational links between local fighters and the group's leadership are murky.

But reports of self-proclaimed IS fighters have been growing since last summer. In Kandahar, the Taliban's birthplace, armed clashes between alleged IS fighters and Taliban have been reported.