Three Iraqi children and two women from the same family were killed Monday when a missile struck their home at Baghdad Airport, where US troops are stationed, the army said.
The latest in a series of attacks on American interests in Iraq came after Washington threatened to close its embassy and withdraw its 3,000 troops if the missiles did not stop.
Attacks over the past year have left relatively few casualties, and Monday’s incident was notable for the number of civilians killed.
The army said they also injured two children.
Twitter accounts supporting U.S. archenemy Iran regularly praise the attacks, but that wasn’t the case on Monday when no group immediately took responsibility.
Half a dozen previously unknown factions have claimed similar attacks under the banner of “Islamic resistance” against the “American occupier” in recent months.
However, experts say they are a smoke screen and that they are former members of pro-Iranian factions of the paramilitary alliance Hashed al-Shaabi, a state-sponsored network near Tehran.
The death of civilians could put the responsible group in an uncomfortable position as the public has been exhausted from years of violence by various armed groups.
The Iraqi army on Monday accused “criminal gangs and groups of outlaws” of “creating chaos and terrorizing people”.
Between October and July at least 39 rocket attacks were directed against US interests in Iraq. Almost the same number has taken place since then.
A total of four soldiers – two British, one Iraqi and one American – as well as one US and one Iraqi contractor were killed in the attacks, while several civilians were wounded.
Iraqi intelligence sources have blamed the attacks on a small group of die-hard Iran-backed paramilitary factions.
– ‘Honeymoons are over’ –
Senior American officers now see pro-Iranian armed groups as a greater threat than the Islamic State jihadist group, which once owned a third of Iraq.
Washington has urged Baghdad to act decisively.
But Iraq has to play a delicate balancing act with the influence of the US and neighboring Iran, which is arming, funding and supporting various armed Shiite factions.
US Secretary of State Mike Pompeo called Iraqi President Barham Saleh this month and threatened to close the American embassy in Baghdad. Iraqi and foreign officials informed the AFP.
This was seen as a new blow to Prime Minister Mustafa al-Kadhemi, who took office as Prime Minister in May.
While he is believed to be Western-oriented, US officials have accused him of not doing enough against pro-Iranian groups.
An Iraqi official told AFP: “The honeymoon is over.”
The American ultimatum was followed by threats of sanctions against high-ranking political and military figures.
Populist Shiite cleric and politician Moqtada Sadr has since called for a commission of inquiry into the rocket attacks, a proposal supported by Kadhemi.
Hashed’s paramilitary alliance has sacked several commanders charged with ties to attacks on Western interests, while declining responsibility for the actions of groups claiming Hashed links and “conducting illegal military acts against foreign interests”.
But more hardline groups have reinforced anti-US rhetoric.
A Western official told AFP, on condition of anonymity, “If Washington enforces its population and withdraws, these groups can brag about driving Americans out of Iraq at a low cost.