Lieutenant-Colonel Christopher Garver, a US military spokesman, declined to comment but said a news conference would be held later on Thursday.
Garver said that the conference will announce the "success" of an operation against the Sunni-led al-Qaeda group, but said that Abu Ayyub al-Masri, the al-Qaeda leader in Iraq, would not be the topic of discussion.
Iraqi officials earlier said that al-Masri was killed this week in a clash with armed fighters north of Baghdad.
The US military has been unable to confirm those reports and no body has been found.
The Islamic State in Iraq was set up in October by al-Qaeda in Iraq and some minor Sunni-led armed groups.
It recently named a 10-man cabinet with a prime minister and portfolios including war, oil and Islamic affairs.
Al-Masri was named war minister, with al-Baghdadi remaining leader of the Islamic State in Iraq. At the time, al-Masri said all followers had to pledge allegiance to al-Baghdadi.
The Islamic State in Iraq has claimed responsibility for a string of attacks, including mass kidnappings, bombings and the shooting down of US helicopters.
The group also denied earlier this week that al-Masri had been killed.
US officials have said that while killing senior al-Qaeda figures in Iraq would be positive, it would not end the group's attacks.
Al-Qaeda is blamed for trying to tip the country into full-scale sectarian civil war.
George Bush, the US president, said on Wednesday, that al-Qaeda was "public enemy number one" in Iraq.
The Pentagon had previously called the Mahdi Army fighters, led by Muqtada al-Sadr, a Shia cleric, the greatest threat to peace in Iraq.
In February, al-Baghdadi vowed to widen attacks to all parts of Iraq instead of just focusing on the capital after Washington announced plans to increase its forces in the city.
Al-Baghdadi had said Bush was giving Muslim fighters a chance "to slaughter the wounded crusader giant and take advantage of the collapsing morale of its soldiers and commanders".