Saddam Hussein's right handman, Ali Hassan al-Majeed, otherwise known as "Chemical Ali", has been executed.
The Iraqi government has confirmed al-Majeed was hanged for crimes against humanity.
Majeed, a cousin of Hussein, was earlier sentenced to death four times for a range of crimes, including ordering the mass killing of Iraqi Kurds.
It is believed that about 5,000 people died when Iraqi jets sprayed the town of Halabja with a mixture of mustard gas and the nerve agents Tabun, Sarin and VX for five hours.
Majid was first sentenced to hang in June 2007 for his role in a military campaign against ethnic Kurds, codenamed Anfal, that lasted from February to August of 1988.
In December 2008, he received another death sentence for his role in crushing a Shia revolt after the 1991 Gulf War.
In March 2009, he was sentenced to death, along with others, for the 1999 killings of Shia Muslims in the Sadr City district of Baghdad.
Majid was arrested in August 2003. The BBC reports he refused to express remorse at any of his trials, insisting that he was acting in the interests of Iraqi security.