Saddam Hussein's use of chemical weapons against Iraqi Kurds in the late 1980s was cited by Western powers as one of the justifications for the Gulf War and the 2003 invasion that toppled him.

Once again, the perilous situation of the Kurds – this time attacked by Islamic State fighters -- has spurred the US and its allies in Europe and the Gulf to use military force in Iraq and Syria. And once again the stateless Kurds are on the move.

Reuters photographers have chronicled Kurdish refugee crises over the years. Pictures from 1991 show men, women and children carrying their possessions, gathering firewood and burying their dead in a refugee camp in Cukurca, Turkey, just across the border from Iraq.

Reuters pictures taken in a refugee camp in Suruc, Turkey in October of this year show familiar scenes – a line of people stretches into the distance as they walk from their homes in Kobani, across the border in Syria, where Islamic State has besieged the town.

The Kurds number up to 30 million people spread through Turkey, Iraq, Syria and Iran, but with no state of their own. Most Kurds are Sunni Muslims, but tend to feel more loyalty to their Kurdishness, rather than their religion.

After the fall of Saddam, the Kurds' semi-autonomous region in northern Iraq became a haven of relative peace in a war-ravaged country – until the Islamic State offensive that started in Iraq in June and turned against the Kurds in August.

The battle for Kobani has become a focal point, not just for the plight of the Kurds, but of the West's confrontation with global Islamist militancy.