U.S. Attack in Iraq Is No Surprise to Many Insurgents

ESAIWID, Iraq — With extraordinary secrecy, and even an information blackout aimed at most of their Iraqi Army comrades, American troops began a major offensive on Tuesday to drive Sunni insurgents from strongholds in Diyala Province. But many insurgents still managed to flee the first villages the Americans went into, showing just how difficult it is to trap the elusive militants.

Because at least half the insurgents escaped before an offensive last June, American planners deliberately kept most Iraqi units in the dark before this one, a tactic that suggests they cannot fully trust the allies who are supposed to pick up more of the fighting as American troops scale back their presence this year.

The militants may have been tipped by leaks or by the visible movements of troops and machinery that precede any operation......