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 himself hanged on December 31, 2006, killed a large number of Shiite leaders during the 1980-88 war with Iran.