Perhaps the most plausible answer that makes the connection is that the insurgents strike at those who cooperate with Americans. But as often as not, maintaining that view requires some imagination.
KIRKUK / Aswat al-Iraq: Casualties from the explosion that ripped through northern Kirkuk city earlier today have increased further, reaching 47 dead and 100 wounded persons, according to a local police source. “A suicide bomber blew himself up inside a restaurant in northern Kirkuk, killing 47 persons and wounding 100 others,” the source told Aswat al-Iraq.A later story suggested that the attack targeted Huweija council members.
I haven't found much background on "Huweija council." I would hazard a guess that it has to do with local security, perhaps as part of a local "Awakening" movement.
Just put the civilians caught in the blast down on the Americans' tab? It makes little sense to me.