The attacks -- at least four in the capital and five in the southern shrine city of Karbala -- appeared deliberately timed to catch Shi'a devotees as they gathered at mosques to mark Ashura. The observances mark the death of one of the most revered figures in Shi'ism in a struggle over Islam's leadership 13 centuries ago. That struggle cemented the schism between Shi'a and Sunni Muslims that remains to this day.
"These acts are targeted against the Iraqi people and the political process toward Iraq's independence and liberation. At the same time, it's an attempt to sow division among the Sunnis and the Shi'a and to make the Sunnis believe that their enemies are the Shi'a and to make the Shi'a believe that their enemies are the Sunnis."
Officials of the best-organized Shi'a political party, the Supreme Council for the Islamic Revolution in Iraq (SCIRI), said they suspect loyalists of Saddam Hussein, backed by international terrorist groups, of trying to "ignite civil strife."
SCIRI spokesman Hamid al-Bayati said "the people behind this act are what remains of the regime, backed by people like Al-Qaeda, with the goal of igniting civil strife. But we are aware of this danger and will not succumb to it."
For now, it is impossible to know if stirring up communal tensions was the sole, or principle, motivation of the attacks. But analysts say there have been increasing signs in recent months that insurgents in Iraq see such a strategy as one of the best ways to destabilize the country and oust the U.S.-led coalition.
Strong evidence that at least some elements among the anti-U.S. forces are seeking to provoke communal fighting emerged with the interception of a letter in January written by a foreign-led extremist group. U.S. officials say the letter was a request from Abu Musab al-Zarqawi -- a Jordanian militant leader operating in Iraq -- to Al-Qaeda, seeking help in driving out coalition troops.
The spokesman for the Coalition Provisional Authority (CPA), Dan Senor, said at the time that "the document...talks about a strategy of provoking violence targeted at the Shi'a, the Shi'a leaders, in hope that it would provoke reprisals [by the Shi'a] against other ethnic groups in the country."
Analysts say today's attacks fit the pattern of many recent attacks in Iraq -- that is, to strike civilian targets in an effort to undermine any sense that stability is returning to Iraq under the CPA.
James Ker-Lindsay, a regional expert at the Cyprus-based Civilitas Research Institute, says the dozens of attacks in recent months constitute what he calls "a pattern of provocations" to destabilize the country.
"I think we are seeing a pattern of provocations across the country, which I think is obviously something the Americans must be extremely worried about," he said.
He notes that the attacks range from bombings against Iraqis cooperating with the CPA, to attacks against Shi'a shrines and celebrants, to attacks against the Kurdish administration in northern Iraq.
The analyst says the attacks are particularly difficult for the coalition and Iraq's emerging local security forces to deal with because they seem to be carried out by multiple groups with their own separate agendas.
"It is worrying insofar that it doesn't necessarily seem that it is just one group that is doing all of this, that there are a number of groups that are determined to destabilize Iraq," he said. "So the United States can't simply pinpoint one particular type of group which is a threat and go all out against them."
He says some groups target the Shi'a in an apparent effort to provoke counterattacks against the Sunni that could spiral out of control, while other groups seem to be targeting the ruling Kurdish factions for local, political reasons.
The Kurdish administration blames a Kurdish-Islamist extremist group suspected of ties to Al-Qaeda for twin suicide attacks in February on the headquarters of the two ruling Kurdish factions in Irbil. Those attacks, which also killed more than 100 people, followed efforts by the Kurdish factions to eliminate that group -- Ansar al-Islam, which had been operating in northern Iraq before the war.
Analysts say one of the curious features of the wave of bombings in Iraq is that the perpetrators do not identify themselves and do not publicize any conditions that they want the U.S. to satisfy as the price for halting them.
Ker-Lindsay says that makes the attacks more difficult to stop because it removes the possibility of negotiating peaceful solutions: "It makes it all the more difficult to fight because you can't enter into a single political process even if you could get these people around the table, [as you could] if it was one group that is behind this or if it was a particular grievance that was being reflected across the country. [Instead,] we are looking at a very fractured situation."
That may mean that the CPA's options in stopping the attacks rest entirely on two hopes. One is that improving intelligence operations in Iraq will enable security forces to disable terrorist groups through continuing efforts to arrest or kill their members.
The other hope is that groups targeted by the bombings will continue to refrain from responding in kind. So far, there are no known cases of Shi'a groups attacking other communities in Iraq, despite what appears to be a deliberate terrorist strategy to provoke them into doing so.