Six bombs in the capital on Tuesday killed at least 35 people, in the second spate of bloody attacks in three days, increasing fears that insurgents are making a return due to a political impasse following elections.
The blasts destroyed residential buildings in mostly Shiite neighbourhoods, leaving bodies and rubble strewn across streets in scenes reminiscent of the height of Iraq's bitter sectarian fighting in 2006 and 2007.
Tuesday's attacks, which also injured around 140 people, followed triple suicide vehicle bombings minutes apart on Sunday targeting foreign embassies which killing at least 30 people and wounding dozens more.
"We are in a war. In our case, it is an open war with remnants of Al-Qaeda and the Baath" party of Saddam Hussein, Baghdad security spokesman Major General Qassim Atta told Al-Arabiya television.
"There has been support for terrorist groups from outside Iraq, from people who don't want to see the political process be a success," he added, without elaborating.
Foreign Minister Hoshyar Zebari, said Sunday's embassy attacks bore the signature of Al-Qaeda and attributed the bombings to groups who wanted to derail the formation of a new government.
"This is a political attack, aimed at derailing the process, sending a message that the terrorists are still in business," Zebari told AFP.
Iraqi political parties are still locked in negotiations in a bid to form a government, nearly a month after the election left four main blocs each without sufficient seats to form a parliamentary majority on its own.
Prime Minister Nuri al-Maliki's State of Law Alliance finished with 89 seats in the 325-member parliament after the March 7 parliamentary elections, two fewer than ex-premier Iyad Allawi's Iraqiya bloc.
Allawi has accused Iran of seeking to prevent him becoming prime minister again by inviting all major parties except his secular bloc to Tehran.
Security officials had warned that protracted coalition building could give insurgents an opportunity to further destabilise the country.
The latest violence follows a Saturday attack south of Baghdad blamed on Al-Qaeda in which security officials said 25 villagers linked to an anti-Qaeda militia were rounded up and shot execution-style by men in army uniforms.
The United States insisted that the upsurge of bloodletting would not compromise its goal of withdrawing all combat troops from Iraq by the end of August.
"I think many expected that insurgents would use this time to roll back the progress, both militarily and politically, that we've seen in Iraq," White House spokesman Robert Gibbs told reporters in Washington on Tuesday.
Gibbs said the White House was in touch with US ambassador to Baghdad Christopher Hill and US commander General Ray Odierno.
Odierno "believes that this does not threaten our ability to draw down our forces later in the year," Gibbs said, but added Washington was very focused on the steps needed to be taken by Iraqi leaders to form a government.
Obama has ordered all US combat troops be withdrawn from Iraq by the end of August and for all American soldiers to be out of the country by the end of 2011.
Although the frequency of attacks by insurgents has dropped significantly since peaking in 2006 and 2007, figures released on Thursday showed 367 Iraqis were killed in violence last month -- the highest number this year.