At least 122 American troops died in Iraq in May, making it the third deadliest month for the United States since the war began.
And as more troops head to Iraq, even higher numbers of U.S. casualties are expected.
In recent months, greater numbers of soldiers have been heading into dangerous ground — the neighborhoods — working in small outposts with Iraqi forces.
More and more of Col. Mike Galloucis' military police from Fort Hood, Texas, are moving into these situations, outside their fortified bases around Baghdad.
"The tactic of getting them out on the street more, so they are physically out on the street — walking on the street, and ... out there and interacting with the populace — does slightly increase the vulnerability of the soldier," Galloucis said.
His police suffered casualties in May, although he won't say how many. He doesn't want to give insurgents too much information.
Snipers are a threat, he says, but the greatest problem is the roadside bomb.
"Everyone has to remember that we are fighting a very savvy adversary that's constantly adapting their tactics, techniques and procedures," Galloucis said. "They are making very lethal roadside bombs."
Earlier in the spring, the improvised bombs accounted for about 60 percent of American deaths. Now it's more than 80 percent.
"The Improvised Explosive Device is the enemy's weapon of choice and that is part of the intense combat," said Brig. Gen. Tony Tata, who is part of a Pentagon team that is searching for ways to defeat the makeshift bombs.
"We find about 50 percent of the IEDs that are out there, so we believe we are experiencing success," Tata said.
Tata acknowledged that as the Pentagon works to come up with a solution, the insurgents are adapting.
"You know, the enemy employs a wide array of these tactics, and he morphs, and as we get good at one thing, he tries to do something else," Tata said.
It's not just in Baghdad, where there are spikes in American casualties. The violence and the number of roadside bombs have increased in Diyala province to the north – and in Kirkuk, even farther north.
"This war is getting more intense," said Tony Cordesman, a defense analyst with the Center for Strategic and International Studies in Washington, D.C. "It is getting more intense than it was towards the end of 2006."
In addition to the number of deaths, the number of wounded is increasing at a greater monthly rate than earlier in the war, Cordesman said. And more than half of those wounded suffer wounds serious enough that they can't return to duty.
Just last week, President Bush said he expects casualties to rise in the coming weeks and months.
Part of the reason is that about 30,000 American troops that make up part of the "surge" in forces will be patrolling in Iraq in an effort to tamp down the sectarian violence — so Iraqis have the breathing space to settle their political differences.
Galloucis says the American troops are starting to make a difference in Baghdad neighborhoods, such as Karada.
"Karada has become a very nice area," Galloucis said. "The interesting thing — it is an area where Sunni, Shia and Christians live among each other without fighting. There are nice restaurants in this area, clean streets, there are markets and new construction all around you."
Cordesman said the real issue isn't whether neighborhoods are getting safer. It's when — and if — the Iraqis can reconcile. So far, there has been little progress.
"If this goes on into the summer and into the fall and the Iraqi government hasn't made real progress toward reconciliation, it's going to be very hard to keep supporting the effort we have," Cordesman said.
The top military commander in Iraq, Gen. David Petraeus, will issue a report on whether the troop surge is succeeding in September.