Eight humanitarian aid organisations on Wednesday called for an immediate ceasefire in northwestern Syria, where hostilities have displaced hundreds of thousands of people in the past two months. The Syrian regime -- backed by Russia -- has carried out an intense air offensive against jihadists and rebels, enabling it to reclaim several towns and villages in the Idlib region despite a freshly-brokered truce. The fighting has displaced some 520,000 people since December 1, the UN said this week. The aid groups -- including the Norwegian Refugee Council, Save the Children, Care and the International Rescue Committee -- labelled the situation a "humanitarian catastrophe". They called for "an immediate cessation of hostilities in addition to immediate access to safety for the millions of civilians currently under fire". "After nine long years of suffering for Syrian civilians, a peaceful solution to this conflict is now more urgent than it ever has been," they said. Syria's war has displaced millions and killed more than 380,000 people -- including over 115,000 civilians -- since it broke out in 2011. phy/po/jxb