Iraq on Thursday executed Saddam Hussein's presidential secretary and chief bodyguard Abid Hamid Mahmud, justice ministry spokesman Haidar al-Saadi said.
"He was executed today," Saadi said, adding: "The ministry of justice implemented the execution sentence against the criminal Abd Hmoud... for genocide," referring to Mahmud by the name Iraqis call him.
Mahmud was number four on the list of Iraqi officials targeted by American forces following the 2003 US-led invasion, behind only Saddam and his two sons Uday and Qusay.
He was captured on June 16, 2003, and eventually sentenced to death on October 26, 2010 along with former deputy premier Tareq Aziz and ex-interior minister Saadun Shaker, for their role in the crackdown on Shiite Muslim religious parties during the 1980s.
Saddam, who was hanged on December 30, 2006, killed a large number of Shiite leaders during the 1980-88 war with Iran.
When in power, Saddam was rarely seen without Mahmud, who shadowed the president and was charged with handing down his orders to Iraqi ministries and ensuring his personal safety.
Both men came from the same village of Aujah, just outside Tikrit north of Baghdad.
With his signature beret and moustache, Mahmud's official title was presidential secretary, but a British government dossier said he was responsible for Saddam's personal security, as well as defence, security and intelligence issues.
The dossier said Mahmud, a lieutenant general in the army, "is regarded by some as the real number two figure in the Iraqi leadership," as he controlled access to Saddam and could override government decisions.
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Mahmud was seen at Saddam's side in his last appearance on television before his capture, aired on April 7, 2003.
Saddam's own execution sparked international controversy after mobile phone video of the sentence being carried out was published on the Internet showing witnesses taunting him as he was about to be hanged.
The footage, which was sold on Baghdad streets after the execution, showed an angry but composed Saddam standing on a steel platform in a dark hall, his hands bound and a rough hemp rope around his neck.
Several members of the party carrying out the hanging could be heard chanting, "Moqtada, Moqtada, Moqtada!" before Saddam is seen falling to his death as the metal trapdoor opens below his feet.
They were referring to Moqtada al-Sadr, a radical anti-US Shiite cleric who rose to prominence after Saddam's fall from power.
Last August, the lawyer for Aziz -- a Christian and close confidant of the executed dictator -- quoted him as calling on Prime Minister Nuri al-Maliki to accelerate his execution because of his worsening health.
"His health condition is very poor and he asked me to convey a message to Mr Maliki, calling on him to execute him as soon as possible," Badie Aref told AFP.
"He said this is his wish now... He asked this because of his dangerous health condition. He is suffering."
Aref said at the time Aziz was being treated well in prison, but had diabetes, high blood pressure, heart problems, prostate problems and stomach ulcers.