Sunday's was the 40th attack against American interests -- including troops, the Baghdad embassy or Iraqi supply convoys to foreign forces -- since US President Joe Biden took office in January.

Two Americans and an Iraqi civilian have been killed in the attacks.

An Iraqi civilian working for a firm maintaining US fighter jets for the Iraqi air force was also wounded in one attack.

The operations are sometimes claimed by obscure groups experts say are smokescreens for organizations long present in Iraq.

Qais al-Khazali, a senior pro-Iran figure in the state-sponsored Hashed al-Shaabi paramilitary force, recently declared that the "resistance" was carrying out attacks and would step them up "unless the US withdraws all its combat forces from across Iraq".

The latest attack came as Washington prepares to launch a strategic dialogue with the government of Prime Minister Mustafa al-Kadhimi, who has regularly received threats from pro-Iran factions.

Kadhimi faces the delicate task of balancing the interests of neighboring Iran and the US, arch-rivals who are both deeply involved in Iraqi politics.

Reporter's code: 50101