Iraqi authorities have announced the arrest of a man they say is al Qaeda's second-in-command in Iraq.

Hamed Jumaa Farid al-Saeedi, also known as Abu Humam or Abu Rana, was arrested a few days ago, according to Iraq's national security adviser Mouwaffak al-Rubaie.

Al-Rubaie said the arrest also led to the capture or death of 11 other top al Qaeda in Iraq figures and nine lower-level members. He would not reveal the identities of the others, or where al-Saeedi was captured, for security reasons.

Al-Saeedi was the second most important al Qaeda in Iraq leader after Abu Ayyub al-Masri, according to the security adviser. Al-Masri succeeded Abu Musab al-Zarqawi, who was killed in a U.S. airstrike north of Baghdad on June 7.

"We believe that al Qaeda in Iraq suffers from a serious leadership crisis. Our troops have dealt fatal and painful blows to this organization," al-Rubaie said.

Al-Saeedi is believed to have been responsible for the person who carried out the bombing of a Shiite shrine in Samarra in February. The incident inflamed tensions between Shiite and Sunni Muslims and triggered reprisal attacks that continue still.

"Al-Saeedi carried out al Qaeda's policies in Iraq and the orders of the slain al-Zarqawi to incite sectarian violence in the country, through attempting to start a civil war between Shiites and Sunnis -- but their wishes did not materialize," al-Rubaie added.

Al-Saeedi had been hiding in a residential building.

"He wanted to use children and women as human shields during the arrest, which is why the operation was based on a very precise military plan to preserve the lives of women and children in the building," al-Rubaie said, adding that there were no casualties during the arrest.

"Hamed al-Saeedi supervised terrorist groups that kidnapped people for ransom, and killed policemen after they received their salaries in order to finance terrorist operations," the security adviser said.

"He used to order terrorist operations using mortars and roadside bombs, which led to the killing of several troops and innocent civilians."

Al-Rubaie said al-Saeedi also supervised the creation of death squads and ordered assassinations, bombings, kidnappings and attacks on Iraqi police and army checkpoints.

"The operations were brutal and merciless," he said.

With a report from The Associated Press