Three of Saddam's former henchmen, including his cousin Ali Hassan al-Majid or "Chemical Ali," were sentenced to death on Sunday for genocide, crimes against humanity and war crimes over the campaign.

Although estimates vary, it is believed that around 182,000 Kurds were killed, and more than 3,000 villages destroyed during the scorched-earth campaign against them from February to the autumn of 1988.

"Chemical Ali," who headed the Anfal offensive, was the most prominent of the three ordered to the gallows by the Iraqi High Tribunal. Two other defendants were sentenced to life in prison while charges against a six former regime official were dropped.

Saddam's regime defended its actions against the ethnic Kurds in northern Iraq as a necessary counter-insurgency operation during wartime, when the eight-year war with neighbouring Iran was at its peak.

The Iraqi court had announced in April last year that Saddam and six co-defendants would face charges of genocide over Anfal.

Saddam, however, was executed on December 30 for crimes against humanity in a separate case, and the charges over the Anfal case were dropped, leaving Majid as the star defendant.

Between 1987 and 1989, Kurds suffered a series of major attacks -- including the notorious gas attack against the town of Halabja in 1988 in which 5,000 people died.

The Halabja massacre, which followed the town's capture by Kurdish peshmergas (warriors) backed by Iranian revolutionary guards, was not included in the trial.

The term Anfal comes from the eighth sura of the Koran and means spoils. The campaign involved the systematic bombardment, gassing and assault of areas in the Kurdish autonomous region in 1988.

By 1986, with the regime under severe strain owing to the 1980-88 war with Iran, large swathes of the Kurdish region had become free of central government control.

In 1987, Saddam charged "Chemical Ali" with bringing the area back under state control, and was accused of making liberal use of poisonous gas, mass executions and prison camps to subdue the north.

Ali began by declaring "prohibited" zones, much like the Vietnam war-era free-fire zones, in which all inhabitants were considered insurgents.

Villagers were moved to defined and easily controlled settlements, while the prohibited areas were shelled and then invaded in classic counter-insurgency tactics.

According to the New York-based Human Rights Watch, what made these campaigns different from other counter insurgency operations was a clear plan to exterminate the Kurds as a people.

"Tellingly, the killings were not in any sense concurrent with the counter-insurgency: the detainees were murdered several days or even weeks after the armed forces had secured their goals," it said in an extensive report on the campaign before the start of the trial.

"Finally, there is the question of intent, which goes to the heart of the notion of genocide," said the report, which provided detailed documents and testimony to support its view.