More than three million Syrians are now registered as refugees and the desperate crisis is only getting worse, the UN's refugee agency says.

The UNHCR says Syria is now "the biggest humanitarian emergency of our era" with almost half of all Syrians forced to flee their homes.

The majority of refugees have fled to countries neighbouring Syria, with 1.14 million now seeking shelter in Lebanon.

More than 190,000 have been killed in Syria's three-year civil war.

Opposition groups in Syria have been fighting forces loyal to President Bashar al-Assad since his government suppressed protests against his rule in March 2011.

The situation has been worsened in recent months by the formation and advance of the Islamic State group, which now controls large swathes of Syria and Iraq.

The UNHCR says one in every eight Syrians has fled across the border and a further 6.5 million are displaced within Syria - half of them children.

Families arriving at refugee camps in neighbouring countries are exhausted and scared, with some having spent a year or more fleeing from village to village inside Syria.

The UN agency says the journey out of Syria is also becoming tougher, with many people forced to pay bribes to armed gangs.

In addition to the registered refugees, Syria's neighbours estimate that hundreds of thousands more Syrians have sought sanctuary in their countries - causing enormous strain.

"The Syrian crisis has become the biggest humanitarian emergency of our era, yet the world is failing to meet the needs of refugees and the countries hosting them," said Antonio Guterres, the UN High Commissioner for Refugees.

"The response to the Syrian crisis has been generous, but the bitter truth is that it falls far short of what's needed."

(BBC)