The State Department said the car bombs that tore through Baghdad cafes and markets, as well as other blasts and shootings elsewhere, were "cowardly" attacks "aimed at families celebrating the Eid al-Fitr" holiday that marks the end of the holy fasting month of Ramadan.
The violence killed at least 61 people and came just weeks after brazen assaults, claimed by an Al-Qaeda front group, on prisons near Baghdad that freed hundreds of militants, and amid high daily death tolls in Iraq.
State Department spokeswoman Jen Psaki, however, went further, reiterating the $10 million award offered for Al-Qaeda in Iraq's purported leader Abu Bakr al-Baghdadi, who is believed to be sheltering in Syria.
"He has taken personal credit for a series of terrorist attacks in Iraq since 2011, and most recently claimed credit for the operations against the Abu Ghraib prison outside Baghdad, the suicide bombing assault on the Ministry of Justice, among other attacks against Iraqi security forces and Iraqi citizens," Psaki said.
"The United States has offered a $10 million reward for information that helps authorities kill or capture Abu Bakr al-Baghdadi. This reward is second only to information leading to Ayman al-Zawahiri, the chief of Al-Qaeda's network," she added.
The State Department response came after a week in which the United States had closed embassies and missions across the Arab world following intelligence reports of a possible Al-Qaeda strike.
Zawahiri was at the forefront of that threat, according to US media reports that said he had ordered a high-profile attack on American interests.
The State Department also noted that Saturday's violence in Iraq follows an especially bloody few months in the country. July saw its worst death toll in more than five years, a statistic that reinforced concern that the nation is sliding back from its fragile democracy that took shape in the wake of the 2003 US-led invasion that ousted Saddam Hussein.
"The terrorists who committed these acts are enemies of Islam and a shared enemy of the United States, Iraq, and the international community," Psaki said.
"The attacks today bear the hallmarks of similar suicide and vehicle bomb attacks in Iraq over the past 90 days. Most of these attacks have been perpetrated by Al-Qaeda in Iraq," she added, expressing condolences to the families of the victims of Saturday's killings.