Iraq today executed Ali Hassan al-Majeed, the Saddam Hussein cousin and henchman widely known as "Chemical Ali", for crimes against humanity.
"The death sentence against Ali Hassan al-Majeed has been carried out today," government spokesman Ali al-Dabbagh said.
Majeed, who earned his nickname because of his use of poison gas, was executed by hanging, a government statement said.
He had received four death sentences for an attack on the Iraqi Kurdish town of Halabja in which thousands were killed.
Mr Dabbagh said in the statement that Majeed was not subjected to any abuse during the execution, unlike the insults heaped on Sunni dictator Saddam himself by Shia Muslim observers when he was hanged in December 2006.
"Everyone abided by the government's instructions and the convicted was not subjected to any breach, chanting, abuse words, or insults," he said.
It was not clear if Majeed was hanged before or after a series of coordinated suicide bombings close to well-known hotels in Baghdad in which more than 30 people died.
Majeed had a reputation for ruthlessness in crushing Saddam's opponents that won him widespread notoriety. Many Iraqis feared him more than the leader himself.
He was captured in August 2003, five months after US forces invaded Iraq and toppled Saddam.
He was sentenced to hang in June 2007 for his role in a military campaign against ethnic Kurds, codenamed Anfal, that lasted from February to August 1988.
Majeed also received a death sentence in December 2008 for his role in crushing one Shia revolt after the 1991 Gulf War and another in March 2009 for his involvement in killing and displacing Shia Muslims in 1999.
His final death sentence came on January 17th for Halabja, when the Iraqi army used poison gas against Kurds. Around 5,000 people were believed to have been killed.
Reuters