The clash occurred near Balad, a major U.S. base about 50 miles north of the capital, Brig. Gen Abdul-Karim Khalaf said.

Khalaf said al-Qaida in Iraq leader Abu Ayyub al-Masri was wounded and his aide, identified as Abu Abdullah al-Majemaai, was killed.

Khalaf declined to say how Iraqi forces knew al-Masri had been injured, and there was no report on the incident from U.S. authorities.

Deputy Interior Minister Maj. Gen. Hussein Ali Kamal said he had no information about such a clash or that al-Masri had been involved.

Al-Masri took over the leadership of al-Qaida in Iraq after its charismatic leader Abu Musab al-Zarqawi was killed in a U.S. airstrike last June in Diyala province northeast of Baghdad.