A Syrian toddler died Sunday when his parents' tent caught fire in southern Lebanon where the family has fled from their country's brutal war, a security official told AFP.

"Mahmud al-Arfan, who was 18 months old, was burned alive when the tent where his family lived caught fire," the official said on condition of anonymity, adding his death had been confirmed.

The child was alone in the tent when a diesel-powered heater caught fire in a makeshift refugee camp on the rink linking southern Lebanon's Ras al-Ain to Naqura.

His parents were out working in the fields at the time.

Two young men were injured trying to put out the fire, which did not spread to other tents.

According to the United Nations High Commissioner for Refugees, more than 842,000 Syrians have fled to Lebanon since Syria's conflict broke out in March 2011.

Lebanon is hosting the highest number of Syrian refugees in the region, followed by Turkey and Jordan.

While both Turkey and Jordan have opened official refugee camps at the borders with Syria, Lebanon's government has refused to do so.

Thousands of refugees now live in apartments -- either as relatives' guests or as renters.

But thousands of others, who cannot afford the cost of living in Lebanon's cities, shelter in hundreds of informal tent settlements scattered across the country.