KABUL/QUETTA: At least two Afghan Taliban commanders have been killed in recent weeks in the Pakistani city of Quetta, militants and police told Reuters, the latest in what officials across the border in Afghanistan have described as a series of assassinations within the Islamic insurgent group.

The motive for the killings and the number of those killed is unclear, but the deaths could make peace between Afghanistan's government and the rebels more elusive as Western troops prepare to leave the war-torn nation.

Afghan officials say several of the victims had been discussing unauthorised peace talks with the government in Kabul.

Officially, the Taliban have denied any such spate of deaths.

“Now the enemy is facing defeat they have turned to baseless propaganda and they call anyone who gets killed a member of the Taliban council or Mullah Mohammad Omar's close confidante,” a Taliban statement said on Friday, referring to the movement's reclusive one-eyed leader.

However, four members of the Afghan Taliban told Reuters last week that the insurgency had killed some of its own commanders because the men were involved in unauthorised talks.

One Quetta-based commander put the figure at 18 such deaths since the beginning of last year.

Quetta is about 80 km (50 miles) from the Afghanistan border and is known as a place of refuge for the Afghan Taliban in the winter months. Afghan officials have long accused Pakistan of supporting the insurgents and giving them sanctuary, a charge which Islamabad has denied.

Both the Taliban and Quetta police say that gunmen shot Noorullah Hottak two weeks ago. Hottak was a member of the Afghan Taliban’s 12-man governing body, named the Quetta shura, said Afghan intelligence officials and a Taliban commander.

But the official Taliban statement acknowledging his death denied that, calling him a “former” warrior.

Last month, gunmen killed Mullah Abdul Malek, another Taliban figure, said a Quetta-based Taliban commander and an Afghan intelligence official.

The Taliban denied his death, and the deaths of two other commanders, in their statement.

“These commanders are alive and busy with their jihad (holy war) tasks,” said the statement.

Around a dozen Taliban members of varying ranks were killed in Quetta in last year's winter, said Rahmatullah Nabil, the head of Afghanistan’s intelligence service.

Nabil said he had investigated the killings and the victims had all sought unauthorised peace talks.

“All 12 had been speaking to the president's negotiators, either directly or through provincial governors or tribal elders,” he said.

Since the killings started up again last month, a senior Afghan official blamed the killings on Pakistani officials, saying they feared losing influence over commanders who started peace talks.

“Pakistan thinks if we're making progress with these (Taliban leaders), that might break their hold on them,” said the official, who asked not to be named.

Pakistani officials say they have no idea who is behind the killings.

“Pakistan has been making all possible efforts to facilitate a reconciliation process in Afghanistan,” said a Pakistani security official who asked not to be named.

A Taliban commander in Quetta blamed the killings on Afghan intelligence, saying they were targeting senior members of the rebel group.

But all sides have a reason to lie about who is behind the killings, said Saifullah Mehsud of the Islamabad-based think tank, the FATA Research Center.

“Many are in the drug trade, others are arms smugglers. It could be a matter of revenge. It's not clear who killed them or why,” he said.