The number of refugees fleeing violence in Syria has surpassed three million, according to the United Nations. That was only a million more than a year ago, but Syrians now account for the world’s largest refugee population under the care of the U.N. CCTV America’s Liling Tan reports.

Violence and extremist tactics carried out by the Islamic State militant group have intensified a crisis that first began as clashes between the Syrian government and opposition rebels.

Now the U.N. High Commissioner for Refugees said it is registering refugees at the fastest rate in history, with one in eight Syrians fleeing in the past year. Lebanon is sheltering more than a million refugees, while Turkey and Jordan are hosting hundreds of thousands. This does not include the 6.5 million displaced within Syria.

The U.N. refugee agency has provided food and access to shelters and schools for 1.7 million refugees in the past year. Donors have contributed more than $4 billion.

The agency said despite the response, the world is failing to meet the needs of both refugees and host countries and more than $2 billion is needed by the end of the year.

The U.N. is also looking to hold certain groups responsible for violence against civilians. This week, the U.N. Commission of Inquiry on Syria issued a report accusing the Syrian government and Islamic State militants of war crimes. Investigators hope to present evidence from the report to the International Criminal Court and compel the international community to take stronger action.

Follow Liling Tan on Twitter @LilingTan