Taliban militants in northwest Pakistan publicly slit the throats of two Afghans on Friday after they were accused of spying for U.S. forces suspected of launching a missile strike in May.

The two men, one of them a former Taliban fighter, were brought blindfolded before a crowd of several thousand people near the village of Damadola in the Bajaur region on the Afghan border before they were executed.

"They were spies. Whoever spies for the Americans will meet the same fate," Qari Zia-ur-Rehman, a Taliban leader in the area, told the crowd before another man slit the throats of the two with a sword.

The crowd shouted Allahu Akbar (God is Greatest) when the Taliban held up the severed heads of the victims who Rehman said were from the eastern Afghan province of Kunar.

Bajaur is one of Pakistan's seven border regions dominated by ethnic Pashtun tribes and a hotbed of support for the Taliban and al Qaeda.

After the killings, shooting broke out in the crowd but it was not clear why. Two people were killed and seven wounded.

Rehman said the two Afghans had spied for U.S. forces who the militants believed were responsible for a missile strike on a house in Damadola in May in which 18 people, including foreign militants, were killed.

Two missiles were apparently fired by U.S. drones and a government official said at the time the strike had apparently targetted a mid-level, Arab al Qaeda member, who had been killed.

Islamist militants have killed scores of people in the tribal belt on the Afghan border on suspicion of spying for U.S. forces in Afghanistan but public executions have been rare.