GHAZNI, Afghanistan (Reuters) - Around 2,000 members of Afghanistan's Hazara ethnic minority held an angry protest on Tuesday after militants killed seven members of their community at the weekend and dumped their partially beheaded bodies.

The killing of the seven Hazara, including three women and two children, during fighting between rival Taliban factions and Islamic State sympathizers, highlighted the risk that worsening sectarianism could add a lethal twist to daily violence sweeping Afghanistan.

The mainly Shia Hazaras have long suffered ill-treatment and persecution in Afghanistan, with thousands massacred by al Qaeda and Taliban militias in the 1990s.

This year, a series of kidnappings and murders of Hazara fueled fears that the group was being deliberately targeted, and the latest killings in the southern province of Zabul triggered a furious wave of reaction on social media.

In a sign of anger among the Hazara, the bodies of the dead were taken to Ghazni, a city in central Afghanistan with a large Hazara community, where crowds marched to the provincial governor's compound in protest.

Bearing the coffins of the dead aloft and chanting slogans against the Taliban, Islamic State and the government in Kabul, the crowd demanded punishment for the killers.

"We ask the government to find the reason behind this serial killing of Hazaras in Afghanistan and bring the perpetrators to justice," Ghulam Ali, a protester, said.

Since the killings of the 1990s, the Taliban has largely avoided specifically targeting Hazaras or Shia Muslims, but the rise in the number of fighters claiming allegiance to the even more hardline Islamic State movement may change that.

Afghanistan is divided among a patchwork of ethnic groups, including Tajiks, Hazaras, Uzbeks and Turkmen, mainly in the north and west, as well as Pashtun, the largest single group, located mainly in the south and east.

While sectarian violence has regularly broken out in the past, it has not been a major feature of the fighting in recent years and any resurgence would add a dangerous new complication for the government of President Ashraf Ghani.

The Taliban's success in seizing control of the northern city of Kunduz and holding it for three days a few weeks ago delivered a huge blow to public confidence in the government's ability to control security.

But in recent days, the Taliban has been caught up in troubles of its own after a splinter faction defied Mullah Akhtar Mansour, who assumed the leadership in July following confirmation of the death of the movement's founder Mullah Omar.

Fierce fighting between the rival factions continued on Tuesday and spread beyond the southern province of Zabul into Herat and Farah in the west, according to Mullah Abdul Manan Niazi, a spokesman for the breakaway faction.