THE Haqqani insurgent network, based in Pakistan and with ties to al-Qaida, is suspected of being a driving force behind a significant number of "insider" attacks by Afghan forces that have killed or wounded more than 130 US and allied troops this year, American officials said.

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 The Associated Press 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. It also could complicate US-Pakistan relations, since the Haqqanis are based mainly in Pakistan.

"Whereas 90 percent of the Taliban problem was a problem internal to Afghanistan, it may be the other way around where 90 percent of the Haqqani problem are challenges on the other side of the border," said Mark Jacobson, a defense analyst at the German Marshall Fund of the US, in Washington.