Coalition forces are moving ever closer to Baghdad on the fifth day of Operation Iraqi Freedom and have begun engaging what is reputedly one of Iraq's best and most powerful Republican Guard divisions.
Senior Pentagon officials insist that, despite a rising casualty toll and Iraq's taking of American prisoners, coalition forces are making good progress in their drive towards Baghdad and the goal of toppling Saddam Hussein's government.
And chief Pentagon spokeswoman Victoria Clarke said allied determination to achieve that objective will not be affected by what she terms Iraq's "deadly deceptions" - including the use of civilian human shields and fake surrenders designed to lure coalition troops into ambushes.
"The despicable behavior of the Iraqi regime has in no way stopped the progress of the coalition. Control of the country continues to slip away from the Iraqi regime and coalition forces are closing in on Baghdad," Ms. Clarke said.
But as they close in on Baghdad, coalition troops have run into one of Iraq's toughest army divisions, the Medina division of the Republican Guard.
Major General Stanley McChrystal of the Pentagon's Joint Staff said it is one of Iraq's best. But he also told reporters he believes its military capabilities have been degraded by coalition air attacks.
"It is one of the best Republican Guard divisions, one of the most powerful. I am sure it has been degraded significantly," he said.
In addition to allied bomb and missile strikes, the Iraqi unit has been attacked by coalition Apache helicopters, one of which went down in the initial engagement and whose crew is missing.
During a Pentagon briefing, General McChrystal revealed what he said was evidence of a weakening of control over the Iraqi military held by senior leaders in Baghdad.
He said Iraqi field commanders have received orders from superiors which they ignored. He gave no details but said there was no evidence any of the disobeyed orders involved the use of chemical or biological weapons.
The general also disclosed a coalition aircraft trying to bomb a bridge in western Iraq about 160 kilometers from the Syrian border accidentally struck a bus.
And in another development, Pentagon spokeswoman Clarke said the coalition is poised at the borders of Iraq to bring in large quantities of relief supplies, including food and medicine. But she said that will have to wait until it is safe enough to do so.