Early reports said one of the men killed by U.S. troops might be the new al-Qaida in Iraq leader Abu Hamza al-Muhajer, also known as Abu Ayyub al-Masri.
Speaking on a television newscast in Iraq, Defense Ministry spokesman Mohammed al-Askari said DNA tests on a body were still under way.
The spokesman said the person in question was killed along with three others in a recent raid. He told television interviewers, they are not sure if it is Abu Hamza al-Muhajer, but they will know more when the tests are finished.
Al-Muhajer, said to be an Egyptian, took over the leadership of al-Qaida in Iraq after his Jordanian-born predecessor, Abu Musab al-Zarqawi, died in a U.S. air strike in June.
Earlier this month, the Iraq National Security Adviser, Mowaffak al-Rubaie, said U.S. and Iraqi forces were closing in on the militant leader.
Al-Qaida is blamed for the suicide bombings that have caused some of the worst violence in Iraq. The U.S. military accuses the Islamist terrorist group of fanning the sectarian conflict in Iraq between Sunnis and Shi'ites that has raised concerns about a possible civil war.