In the past 10 days more than 200 Iraqis have been killed by improvised explosive devices -- a sudden uptick in militant activity coinciding with U.S. withdrawal from population centers.
The worst blast took place in Kirkuk, a northern city, where about 75 people were killed. In Iraq's capital at least three bombs have gone off in busy marketplaces in the Shiite enclave of Sadr City and neighboring communities. Those bombings were blamed on al-Qaida, whose members are nominally Sunni, and were believed gambits to shake public confidence in Iraqi security forces and reignite sectarian warfare.
And at least five blasts in northeastern Baghdad have specifically targeted U.S. troops.
"Today we are in need of unity as they (al-Qaida and Shiite extremists) have shown their teeth again," Prime Minister Nouri al-Maliki said Saturday.
"We have to trust our security force to administer security and pursue al-Qaida remnants and criminal gangs."
The pullback by U.S. troops and the assumption of security responsibility by Iraq comes under the Strategic Framework Agreement between Washington and Baghdad that was hammered out late last year in tough negotiations. It took effect Jan. 1, replacing an expiring U.N. mandate, and governs continued U.S. military presence in Iraq, which must completely end by Dec. 31, 2011.
Among key provisions insisted upon by Iraq was the transitioning of urban security responsibility to its own forces.
For weeks U.S. soldiers in Baghdad and elsewhere have been relocating to facilities outside cities and turning over installations that were once exclusively U.S. occupied but later shared with Iraqi troops. Among them in Baghdad was Joint Security Station Sadr City, a key base on the edge of the Shiite community of the same name. It was in and around Sadr City last year where U.S. forces battled the militia of anti-American cleric Moqtada Sadr, which was raining down rocket fire on the International Zone in a direct challenge to the authority of the national government.
The International Zone, also known as the Green Zone, is the location of Iraqi government offices and the U.S. Embassy.
As Americans withdrew, Iraqi police forces boosted their presence at security checkpoints around Baghdad and Iraqi troops stepped up patrols in vehicles. All scheduled leaves for Iraqi security forces in Baghdad and elsewhere in the country were canceled.
"The training wheels are already off," said U.S. Army Sgt. 1st Class John Shumaker of the 1st Battalion, 5th Cavalry Regiment. "If not now, when? They're ready. They need to go and take that next step.
"They're going to take some bumps, yes, but they have to stay the course and they'll get over them."
Shumaker's battalion is one of a few U.S. units that will remain in Baghdad to continue training their Iraqi counterparts -- if requested by the Iraqis -- and provide support for them if needed, wanted and asked for.
The unit is based on Forward Operating Base Shield in northeast Baghdad. Technically a multinational installation, it hasn't received an order to vacate from the Iraqi government.
Its soldiers will no longer patrol in daylight. Indeed, they won't leave the facility except to back up Iraqi forces when requested.
Iraqis celebrated the handover early. On Monday loudspeakers at police checkpoints played patriotic music, and thousands gathered in a large square to cheer and dance.
Whether they are cheering or dancing in the weeks ahead is another matter.