"KABUL, Aug 31 (Reuters) - An adolescent boy and a young girl have been beheaded in two separate incidents in Afghanistan, local officials and police said on Friday, in the latest brazen attacks that have raised fresh questions about a splintering Taliban.

A 12-year-old boy was kidnapped and killed in southern Kandahar province on Wednesday, his severed head placed near his body to send a warning to police, said provincial governor spokesman Jawid Faisal.

The brother of the boy, neither of whom were named by officials, was a member of the Afghan Local Police (ALP), a U.S.-trained militia charged with making Afghans in Taliban strongholds, like Kandahar, feel more secure, Faisal said.

"It's a Taliban warning to the ALP and to others who support the government," Faisal said of the killing, which happened in Kandahar's Panjwai district.

Separately, a 6-year-old girl was beheaded in eastern Kapisa province on Thursday, said provincial police chief Abdul Hamed.

The murders follow the shooting or beheading of 17 young revellers attending a party in southern Helmand province this week, which officials said was the work of the Taliban, a charge the group also denied.

"What we're seeing could be a new tactic by the Taliban to behead civilians to intimidate the population," said Faisal.

In Kandahar's Zhari district, officials also said on Friday that a 16-year-old boy accused by the Taliban of spying for the government was beheaded and skinned in late July."