TRIPOLI, Lebanon — The number of Syrian refugees in Lebanon has surpassed 1 million, the U.N. refugee agency said Thursday, calling it a "devastating milestone" for the tiny Arab country with about 4.5 million people of its own.
Also, three years after Syria's conflict started, Lebanon has become the country with the highest per-capita concentration of refugees recorded anywhere in the world in recent history, the UNHCR said.
As a result, Lebanon is struggling to cope with a massive crisis that has become an unprecedented challenge for aid agencies, UNHCR said.
Along with the social and economic strain of the refugees, Syria's sectarian war has also frequently spilled over into Lebanon with deadly clashes between factions supporting opposing sides in the fighting next door.
Militants from Lebanon's Shiite militant group Hezbollah are fighting alongside President Bashar Assad's forces in Syria while many among Lebanon's Sunni population support the rebels trying to topple him.
The 1 million Syrians are a huge burden for Lebanon, which has a 4.5 million-strong population, the UNHCR said. The agency registers 2,500 new Syrian refugees daily in Lebanon - more than one person per minute.
In addition to the registered refugees, there are tens of thousands of other Syrian refugees who are not registered and Lebanese officials estimate the number of unregistered refugees to be as high as 400,000.
The 1 millionth refugee was registered in the northern city of Tripoli on Thursday, and only accepted to give his first name, Yahya, concerned that his relatives back in Syria would be targeted.
The 19-year-old man said he was evacuated earlier this year from the central city of Homs and crossed into Lebanon with his mother and two sisters on March 8.
"The influx of a million refugees would be massive in any country. For Lebanon, a small nation beset by internal difficulties, the impact is staggering," said Ant�nio Guterres, UN High Commissioner for Refugees in a statement. "Lebanon hosts the highest concentration of refugees in recent history."
UNHCR said the influx is accelerating.
In April 2012, there were 18,000 registered Syrian refugees in Lebanon and by April 2013 they reached 356,000 and at the beginning of April this year they reached, 1 million.
The World Bank estimates that the Syria crisis cost Lebanon US$2.5 billion in lost economic activity during 2013 and threatens to push 170,000 Lebanese into poverty by the end of this year, the UNHCR statement said.