KABUL, Afghanistan - As thousands paid their respects this week to a slain northern Afghanistan police commander, a top lawmaker sounded an ominous warning: He and three other minority faction leaders are on a Taliban hit list and could be next.

Conflict between the Taliban - who come mostly from the biggest group, the Pashtuns - and members of its ethnic minorities is nothing new in a nation whose history is scarred by civil strife. But rising ethnic tension is jeopardizing efforts to make peace with the Taliban after nearly 10 years of war.

Minorities already worry that President Hamid Karzai, a Pashtun, will make too many concessions to their Taliban enemies to shore up his Pashtun base and craft a peace deal. Some ethnic factions have started taking weapons out of mothballs to be ready for a fight.

Whatever support for peace talks Karzai has won from minority groups could erode if extremists continue to pick off their leaders one-by-one.

Gen. Daud Daud, an ethnic Tajik, was the fifth minority leader slain by extremists in recent months. He was killed Saturday in one of a series of high-profile bombings that insurgents have been carrying out across the nation. His death comes just weeks before the United States is to withdraw some troops.

NATO and Afghan forces have captured a suspect in the attack that killed Daud and five others, including two German soldiers, the coalition said Wednesday.

NATO said the man belonged to the Islamic Movement of Uzbekistan, a Taliban- and al-Qaeda-linked movement operating in northern Afghanistan, and was captured in a night raid Monday.

The Taliban claimed responsibility for the attack.

The July drawdown - the symbolic start of a gradual withdrawal of international forces over the next several years - has spawned fears the country will descend into civil war when foreign troops leave.

"There are some hands who are trying to split people from each other," Karzai told reporters Tuesday.

Afghan Interior Minister Bismullah Khan Mohammadi has stressed the need for a strong force that represents all faces of Afghanistan.

A unified force is needed to shoulder security at the end of 2014 when international combat forces are scheduled to be gone or fall back into supportive roles, he says.

Currently, 44 percent of Afghan policemen and soldiers are Pashtuns, 43 percent are Tajiks, Hazaras, or Uzbeks, and 13 percent are from other ethnic factions, according to the U.S.-led coalition's training mission.

Lawmaker Yunus Qanooni, a Tajik and former speaker of the lower house of parliament, said at Daud's memorial service Monday that insurgents now were threatening to kill him and three other prominent members of ethnic minorities. He did not say how he knew about the Taliban hit list.

Karzai needs minority groups - loosely known as the Northern Alliance - to back his efforts to reconcile with the Taliban.

That's because, while Pashtuns make up 42 percent of the population, collectively the minority Tajiks, Hazaras, Uzbeks, and other smaller groups outnumber them. Without minority support, the country risks a de facto partition into a Pashtun south and a "minority" north.