Kabul: The Haqqani insurgent network, based in Pakistan and with ties to al Qaeda, is suspected of being a driving force behind a significant number of the "insider" attacks by Afghan forces that have killed or wounded more than 130 US and allied troops this year, American officials said on Saturday.
Until now, officials had said the attacks seemed to stem either from personal grievances against the allies or from Taliban infiltration.
The Taliban has publicly claimed to be orchestrating the campaign to subvert the US-Afghan alliance.
New data provided to a news agency this week also reveal that in addition to 35 US and allied troops killed in insider attacks last year, 61 were wounded. Those included 19 in a single attack in the eastern province of Laghman on April 16, 2011, in which six American servicemen were killed.
Thus far in 2012 there have been 53 killed and at least 80 wounded, the figures showed.
Haqqani involvement in the plotting would add a new dimension to that group`s insurgent activity, which has been marked largely by spectacular attacks against targets inside Kabul.
Haqqani leaders have pledged allegiance to Taliban leader Mullah Omar, but the group largely operates independently.
The two groups have a shared interest in evicting foreign forces.
The US officials said that although there is no hard evidence tying the Haqqanis to specific attacks, the pattern of shootings and the movements and backgrounds of some of the shooters, including travel into Pakistan shortly before the shootings, point to a likely connection to the group Washington last month officially labeled a terrorist organisation.
The officials spoke on condition of anonymity in order to discuss inferences drawn from internal US military analyses of a string of murderous attacks over the past two years that have angered the allies, embarrassed the Afghan government and threatened to undermine the war effort.
The officials were not authorised to make the comments publicly.
The US-led military coalition recently slowed, temporarily, its partnering with some Afghan forces, partly in response to a recent spike in insider killings.