The deputy premier was forced to flee a rally he was addressing on Sunday, an Agence France-Presse (AFP) reporter said.
The demonstrators, who have blocked a key highway connecting Iraq to Syria and Jordan for the past week over the alleged targeting of their Sunni Arab minority by the Shiite-led government in Baghdad, threw water bottles, stones and shoes at Saleh al-Mutlak before grabbing and hitting him.
Mutlak, who is himself Sunni and from Anbar province where the protests have been staged, managed to escape after federal police arrived and fired their weapons into the air.
An aide to Mutlak, speaking on condition of anonymity, said the deputy premier was all right and was returning to Baghdad.
Mutlak had arrived at the rally site earlier on Sunday and began addressing the crowds, which have numbered in the tens of thousands at their peak over the past week, from an elevated platform.
Stones and shoes
But as he began speaking, demonstrators shouted "Traitor!" in an apparent reference to his being in the national unity government they were protesting against, and began throwing bottles of water at him, an AFP journalist said.
They then began hurling stones and shoes, at which point Mutlak's personal security detail formed a protective ring around him and escorted him from the platform, firing their weapons above the heads of protesters.
But demonstrators followed them and broke through the security cordon, grabbing Mutlak's clothes and hitting him in the mouth, drawing blood. Federal policemen then intervened, firing into the air to disperse the crowd, and Mutlak was driven off in an unmarked civilian car.
Two people were wounded by the gunfire. The rallies began on December 23 after the arrest three days earlier of Finance Minister Rafa al-Essawi's guards on terrorism charges, prompting the minister to call for Prime Minister Nuri al-Maliki to resign or be removed.
Demonstrators, who have massed in Sunni-majority provinces such as Anbar, Nineveh and Salaheddin, have said anti-terror laws were being used by the Shiite-led government to target their community. – Sapa-AFP