Visibility fell to less than one kilometre (barely half a mile) in central and southern cities as the storm cloaked the region in an eerie orange haze, AFP photographers reported.

Basra and Najaf airports both closed for the duration of the storm, which began to dissipate on Tuesday morning.

Health ministry spokesperson Saif al-Badr said Basra was the worst-hit province, accounting for more than 1,000 of the 3,747 hospital admissions attributed to the sandstorm.

Many of those who dared to venture out in Basra wore face masks to protect themselves from the choking dust, an AFP photographer reported.