Refugees of the Syrian civil war are citizens and permanent residents of Syria who fled the country in the course of the Syrian civil war. The pre-war population of Syria was estimated at 22 million (2017), including permanent residents. Of that number, the United Nations (UN) identified 13.5 million (2016) as displaced persons in need of humanitarian assistance. Since the start of the Syrian civil war in 2011 more than six million (2016) were internally displaced, and around five million (2016) crossed into other countries, seeking asylum or placement in Syrian refugee camps. It is believed to be one of the world's largest refugee crises.
Armed revolts started across Syria in 2011 when security forces launched a violent campaign to halt nation-wide protests.