The United Nations says the number of refugees to have fled Syria for Lebanon now officially exceeds one million.
The UNHCR refugee agency said Lebanon now has "the highest per capita concentration of refugees worldwide".
More than 2.5 million have left Syria since the start of the conflict three years ago. Large numbers been taken in by Turkey, Jordan, Iraq, Egypt and others.
However, Lebanon is bearing the biggest burden of all - the number of Syrian refugees there now amount to a quarter of the population.
The government says there is huge pressure on Lebanon's economy, schools and resources.
The BBC reports international aid agencies are finding it increasingly difficult to cope with the flow of refugees.
The UNHCR has only received 14% of the $US6.5 billion funding it has asked for.
"Every day, UNHCR in Lebanon registers 2,500 new refugees: more than one person a minute," the agency said in a statement.
About 9.5 million people, almost half of Syria's population, have fled their homes since the start of the conflict.