Young Syrian refugees pose for a photograph in Lebanon's Beka'a Valley, Oct. 21, 2013.

The United Nations estimates that at least 500,000 Syrian children are now living in Lebanon, mainly in refugee camps.

Many of these children have been forced to work for a living, starting as young as 7 years old, to help support their families. In Beka'a Valley, women and children earn around $5 a day picking vegetables in fields close to the camps.

See more: Syria's youngest refugees labor in fields to help feed their families

View of a refugee camp in the Beka'a Valley, Lebanon. The camps are surrounded by fields in this fertile farming area, Oct. 21, 2013.

A Syrian woman in a refugee camp at dawn, Oct. 21, 2013.

Refugee children in this makeshift school, some as young as 7, told CBS News' Clarissa Ward they also work in the fields, Oct. 21, 2013.

A Syrian man poses with some of his children on Oct. 21, 2013, including a three-month-old who was born in the refugee camp. He says he struggles to provide for his family.

A young girl carries an infant across a plank leading into a refugee camp, Oct. 21, 2013.

Batool, 10, center, waits with her father, right, for a truck to take her to the fields, Oct. 21, 2013.

The eldest of six children, Batool earns money for her family by picking vegetables. It is the only income her family has had since settling in the refugee camp in the Beka'a Valley four months ago, after fleeing Idlib, Syria.

A woman sweeps around her makeshift home in a refugee camp for Syrians, Oct. 21, 2013.

A Syrian boy picks green beans near his refugee camp in Lebanon's Beka'a Valley, Oct. 21, 2013.

A woman and toddler, Syrian refugees in Lebanon, Oct. 21, 2013.

Refugee children attend a makeshift school in the Beka'a Valley, Oct. 21, 2013.

Teenage Syrian refugees working in the fields, Oct. 21, 2013.

A Syrian refugee and her young child in the bean fields, Oct. 21, 2013.

UNICEF and partner charities say they only have enough makeshift schools in Lebanon for a fraction of the Syrian children living there, Oct. 21, 2013.