Jordanian-born al-Zarqawi, who has a US$25m (A$33m) bounty on his head, has claimed responsibility for a string of insurgent attacks in Iraq and the execution of hostages.
After Osama bin Laden, he is Washington’s most-wanted man.
The US has reacted cautiously to the statement posted on a militant website that often publicises his group, saying there is no way of verifying the claim.
“Islamic nation, brothers in unity, we pray God that our sheikh, Abu Musab al-Zarqawi, recover from the wounds he has sustained,” said the statement issued in the name of his militant organisation’s “information department”.
“May God heal you, the most dear of the mujahideen (Islamic fighters). May God give you strength,” said the al-Qaeda Organisation in the Land of Two Rivers.
No details were given how he was injured but the language used indicated they could be severe.
“The injury of our leader is an honor and an incentive to tighten the noose on the enemies of God and a reason to step up our attacks on them,” the statement said, citing Koranic verses that referred to the Prophet Mohammad being wounded in battle.
If al-Zarqawi were captured or killed it would mark a significant breakthrough for US and Iraqi forces, although analysts warn it wouldn’t put an end to the violence.
“It will have an impact, but for that group only. I think the insurgency itself will carry on probably much as it is,” David Claridge of Janusian Security Risk Management told Reuters.
“In Saudi Arabia, al Qaeda has had several successors when leaders have been killed. They may not have the same experience or power as Zarqawi but they would continue, perhaps with less zeal,” he added.
The announcement follows unconfirmed reports al-Zarqawi was wounded in fighting in western Iraq and had sought treatment at a hospital in Ramadi
The elusive al-Zarqawi managed to elude by US-led forces in the massive “Operation Matador” earlier this month near the Iraqi-Syrian border.
In April the US military announced they’d captured his driver but just missed al-Zarqawi at a checkpoint in western Iraq in February.
He’s believed to have jumped out of a truck leaving his computer and a large sum of cash behind.
The statement was released on another day of violence in Iraq, with four US soldiers and two Iraqis killed in attacks in Baghdad on Tuesday.
They came a day after a wave of attacks and bomb blasts killed at least 56 Iraqis and five US troops.
In the past four weeks more than 600 Iraqis have been killed, deepening sectarian tensions and prompting Shiite and Sunni Arab leaders to open talks on reconciliation.