Insurgents on Saturday killed two American troops in eastern Afghanistan, an area that has seen heavy fighting in recent months, the U.S. military said.
No other information about the deaths was disclosed, pending notification of family members.
But a U.S. military official said two U.S. special operations forces were killed by small arms fire in Wardak province, southwest of Kabul.
The official spoke on condition of anonymity because he was not authorized to disclose information about the deaths.
So far this year, 296 international troops, including at least 257 Americans, have been killed in Afghanistan.
In the south, an Afghan policeman was killed and another was wounded when a remote-controlled bomb planted on a motorbike was detonated in Sangin district of Helmand province, according to provincial spokesman Ahmad Zarak.
In neighboring Kandahar province, a roadside bomb killed another Afghan policeman in Kandahar city, said provincial spokesman Ahmad Jawed Faisal.
Meanwhile, The Associated Press reported that American officials say 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 the "insider" attacks by Afghan forces that have killed or wounded more than 130 U.S. and allied troops this year.
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 U.S.-Afghan alliance.
New data provided to The Associated Press this week also reveal that in addition to 35 U.S. 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 U.S.-Pakistan relations, since the Haqqanis are based mainly in Pakistan.
The U.S.-led military coalition said Saturday that a senior Taliban leader with links to Haqqani had been arrested in the eastern province of Paktia. It said he is "suspected of maintaining working relationships with multiple Haqqani senior leaders" and of planning and directing attacks on Afghan and coalition forces, smuggling weapons, and placing roadside bombs in the neighboring province of Logar.
The U.S. officials said Friday that although there is no hard evidence tying the Haqqanis to specific insider 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, which the U.S. last month officially labeled a terrorist organization.
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