Al Qaida leader arrested.
The man, who was not identified, was arrested on Tuesday and was the leader of assassination, kidnapping and bomb-making cells in Baghdad, Maj Gen William Caldwell said.
In a separate announcement, Iraqi authorities said that police killed Abu Jaafar al-Liby, a senior member of al Qaida in Iraq, during an operation in Baghdad three days ago, Interior Ministry director of operations Brigadier Abdul-Karim Khalaf said.
Four other insurgents were killed and two others were arrested during the raid, Khalaf said.
He added that al-Liby was in charge of the Baghdad sector and was either the second or the third man in al Qaida in Iraq, according to Khalaf.
Two letters were found with al-Liby, he said.
One was for al Qaida leader Osama bin Laden and the other was for Abu Ayyoub al-Masri, who took over al Qaida in Iraq from Jordanian-born terrorist mastermind Abu Musab al-Zarqawi after he was killed in an American airstrike north of Baghdad on June 7.
Both letters pledged loyalty and promised more attacks.
Al-Masri is also known as Abu Hamza al-Muhajer. US officials say they believe he is an Egyptian known as Abu Ayyoub al-Masri, an explosives expert who trained with al-Zarqawi in Osama bin Laden's camps in Afghanistan.
It was not know if the killing announced by Iraqis was in any way related to the operations that led to the arrest of the unidentified al Qaida terrorist described by Caldwell.