The US army in Baghdad plans to deploy large numbers of troops with Iraqi special police units to try to curb suspected sectarian militia activity among the police.
"We're going to try to wrap ourselves around them," a senior US military official told reporters, speaking on condition of anonymity.
"The lines are blurred now and it's not easy to determine that some operation tonight was directed ... by the Interior Ministry or ... by some people in uniform ... who are part of somebody's posse," he said. "We're trying to control that."
Unnamed senior US official on Iraqi police commanders
Strained relations between US forces and Iraq's Interior Ministry were highlighted last month when American troops found dozens of abused Sunni Arab prisoners at a secret ministry site in Baghdad.
Two more such secret jails have since been discovered in Baghdad, the official said, as well as one in northern Iraq.
US officials have voiced mounting concern that violence by pro-government, pro-Iranian Shi'ite militias could prolong unrest by alienating minority Sunni Arabs, so delaying a US withdrawal.
Nine special police brigades in Baghdad each have 40 to 45 US personnel attached to them to train and liaise with the US command, he said; the plan would raise that to hundreds of Americans, similar to ratios seen with the Iraqi army.
"By hugging the enemy, wrapping our arms around them, we hope to control them ... like we did with the army," he said, noting that the Interior Ministry was not enthusiastic about the idea. The plan was likely to be approved shortly, he said.
"They can tell us to get lost but we ain't going to get lost," the official said of Iraqi commanders. "If we find they're breaking the law, then we're going to arrest them."
Officials at the Interior Ministry were unavailable for comment. Last week, the US ambassador called for non-sectarian leadership at the ministry.